| All Things HVAC

All You Need to Know and More about Make Up Air Units

January 19, 2016 by itadmin Leave a Comment

Building proprietors, managers and home owners alike find the need for high indoor air quality rocketing to the top of their priority list as times goes by and requirements become higher and higher. Here is a guide explaining what make up air units are, when can they be used and if it’s the right choice for you, in order to help you decide if you should get one or not.

What are make up air units?

By definition, they are units meant to supply conditioned air, whose temperature and humidity is completely controlled, into a building, in order to replace the air that has been removed by the exhaust systems or by combustion. Their main quality is that they bring fresh outside air through their ventilation heating or cooling equipment, rather than recycling or recirculating the already existent one.

Does it make sense for you to use a makeup air unit?

Usually these mechanical air providers are used by big buildings, like office spaces or apartment blocks, which need to be zoned. For buildings with such purposes, make up air units are very attractive because zoned energy use is very efficient and will give everybody the chance to control their environment, temperature and humidity.

This basically means that every apartment owner or every member of the staff with his own private office will get the chance to use energy, heating and air supplies as they see fit. It’s also very attractive cost-wise. For example, building owners who rent out their lodgings use it to hook and reel in their tenants, by presenting them with this option, instead of having their temperature and air regulated for the whole building. It’s also extremely efficient cost-wise, because a tenant can always turn it down or turn it off altogether if they feel the need and reduce costs significantly.

Makeup air units are also used by buildings such as hospitals, meaning construction structures that cannot reuse the air inside a room. Hospitals have the greatest need for fresh air, probably, of all buildings and this is why they normally go for makeup air units. Nothing should contaminate their air and make people sick. But there are other types of buildings which use it as well, such as paint shops and factories or restaurant kitchens, which, again, cannot afford to recycle the air inside.

Therefore, if you find yourself in one of these situations or have such a project in mind, then a makeup air system is definitely for you. However, if you’re keen on it, you can also use it inside your personal home. If, for example, you cook a lot and you have a big kitchen and it needs kitchen ventilation or if have toddlers around the house and need to refresh the air as often as possible.

However, it was not designed for use in your car. You can use it if you have a spray booth, you can also purchase the small or mini version of it, which can be designed as portable, like the Soleus model. They are not very loud, they come with special installing kits and plans and they can also be used in residential areas, as they have kitchen ventilator options. Make sure to follow the regulations.

Location

Makeup air conditioner units are often associated with rooftop units and that’s why people tend to believe that they should be placed on the roof, but that’s not true. It only happens because they are quite large, having also compressors, controllers, a pump, a gas lantern, vents and an exhaust tank. You can also place it in a mechanical room, if you so see fit. Actually, in most hospitals, they are placed in such special designed rooms, where they can be accessed a lot more easily and quicker than on the roof. In case of emergency, a specialist or a mechanic enters the room and fixes the unit instead of climbing to the roof. It’s also easier when it comes to cleaning it, as it is done with a brush.

Budgets and prices

First thing you have to understand about makeup units is that the price is based on the design and model. Therefore, before deciding to buy a machine, you must take into consideration what goes in each of them. Normally, the usual design cost is based on the ‘per square foot of space’ system. Historically, the grounds for that were represented by standard unitary equipment and very little or no outside air at all. Therefore, when your ventilation requirements ask for a dedicated unit, that’s when the cost per square foot will increase, at least on paper. Deals can, of course, be made.

What this basically means is that you need to do some research and be very well informed about the design, so that you can plan your budget accordingly. But, indeed, tradeoffs can be made and you can also analyze some competing system types so that you can see which one better suits your needs and/or your budget.

Also, take into consideration the first costs as well as the operating costs, when thinking about prices and budgets and plan accordingly. A good idea is making your purchase from specialized sellers, such as Modine, Aaon, Cannon Fabrication, Inc., which produce rooftop accessories, or Mobile Air and have specialized officers to come mount them.

Why is air replacement necessary?

Some might think that simply ventilating a space is enough, but that is not always the case. Depending on the activity performed inside, its size and its requirements, a makeup up air unit which replaces air might be necessary for the following reasons:

So that exhaust hoods must always operate properly. An exhaust hood, also known as extractor hood or basket or, more commonly as a cooking canopy is a type of device that has a mechanical fan built in, which is plug based. It usually hangs above your stove in the kitchen and it’s used to capture and remove airborne grease, hot dry air, fumes, gases, smoke, water vapors, odors, steam and heat caused by cooking on the kitchen stove. Some are designed as easy fresheners, so that they bring in fresh air from the outside, others recycle the air while in traffic, filtering it for grease and bad smells at the same time, before reintroducing it into the room. However, kitchens are not the only place you can find them. They are also components of the makeup air unit and work pretty much in the same way. And it’s very important that they work properly. If there isn’t enough makeup air and there is too much negative air pressure, that can lead to static pressure, which the fans will need to overcompensate. What this does is cause a diminishing of the “cubic feet per minute” air coming from the exhaust fans. This will cause a lot of unwanted negative air flow pressure.

To eliminate all cross drafts which run at high speeds in the rooms between doors and windows, no matter the time of year – this process is linked to the one above, meaning that cross-drafts depend very much on the quantity of negative pressure created. If there is a lot of it, then the drafts can be substantial. In turn, drafts interfere with the proper functioning of the exhaust hoods. But, the main negative thing that can happen is the fact that, if you don’t solve your cross drafts problem, they might carry contaminated air from one space to another. This makes for a very serious thing if, for example, we are talking about a hospital, where you cannot have infected air dispersing randomly between sections or, if you are running a restaurant and the smell of cooking food invaded the actual dining rooms. It’s the same thing with paint factories, where fumes from drying paint can cause serious damage or with construction sites where the dust and tiny debris particles can float back into clean rooms.
To make sure natural draft stacks operate fluently. The stack effect basically means air movement inside and outside of buildings, due to air buoyancy, which happens because of the different densities inside and outside air have. If the stack effect grows in intensity, so will the buoyancy. It’s very important because it is known to be the cause of several fires of great force, like the King’s Cross Fire. This is the main reason why an air replacing unit is so necessary. It removes combustion products such as carbon monoxide, it keeps the pilot light in burners alive, or it announces via its horn that it’s out, it’s a temperature controller and it regulates corrosion damage in stacks.
It’s also necessary in order to reduce cold drafts intake, which can cause serious discomfort to people and kids. By means of consequence, when the cold downdrafts are reduced or eliminated altogether, the temperature rises and money are saved as far as heating and energy are concerned.
To eliminate the different pressures related to doors. One of the reasons doors are usually very difficult to shut or open has to do with high pressure differentials. This can cause injuries and can also be a safety hazard for workers.

Here are the things you need to know about air makeup conditioning units. Remember to consider your budget first as well as your needs and all the safety reasons they involve. All these things will help you decide if this is the best solution for your space.

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BTU Made Easier

January 5, 2016 by itadmin Leave a Comment

The abbreviation for the British thermal unit, BTU is a unit of work that is the rough equivalent of 1055 joules and 252 heat or little calories. What is BTU? Used in the United States and sometimes in the United Kingdom, the British thermal unit stands for the amount of thermal energy that is required to increase the temperature in one pound of water by one degree Fahrenheit. The foot-pound-second system is an English system that uses the BTU, while other countries employ the International System of Units, which uses joules. BTU is also known as Btu or B.Th.U.

Every combustible material has a British thermal unit rating. To answer the question what is a BTU, consider that a pound of burning wood will generate around 7,000 British thermal units, a gallon of fuel oil will generate 140,000 BTU, while a gallon of liquid propane will produce roughly 92,000 BTU. Wondering about bigger BTU generators? A barrel of gasoline is able to produce 4.35 million BTU and a ton of coal produces 20 million BTU. Despite being called the British Thermal units, this measuring non-metric unit is more used in the United States and Canada than in the United Kingdom. In the countries that employ the Btu, this unit is also used for measuring natural gas prices. One cubic foot of natural gas equals 1,034 Btu units.

Let’s look at a specific example: if you want to boil one gallon of water that has 60 degrees Fahrenheit, you will need approximately 1,200 BTU to bring the water to a boiling point, which is 212 degrees Fahrenheit.

At the same time, the British thermal unit is used for quantitative specifications regarding the energy transferring and producing attributes of cooling and heating units, like ovens, refrigerators, air conditioners and furnaces. The computer equipment’s heat output is usually specified in order to be taken into account when technicians set out to plan the climate control system within a house or a building. Expressed in BTU per hour, the output of computer device heat is the equivalent of one watt of heat dissipation.

BTU, BTU / Hr, Input BTUH, Output BTUH, MBtu

When discussing heating a building, the BTUs will describe the heat that is produced by the fuel or energy, which can come from various sources: LP gas, electricity, natural gas or oil. When talking about cooling a building, the rated capacity for the air conditioning unit or the heat pump will be expressed in BTUs. This refers to the removal of a given amount of heat from a room.

BTUH, BTU / Hr or British Thermal Unit per hour refers to the number of BTUs of energy that are generated (for heating units) or removed (for air conditioning units) in an hour.

Sometimes, heating, ventilating or air conditioning units will display two BTU capacities on the appliance label. The first one is Input BTUH, which refers to the energy used up by a heating or cooling system and which is measured per hour in thousands of BTUs.

The Output BTUH points to the heat output or cooling capacity from the cooling or heating unit. This will be measured in thousands of BTUs/ hours and sometimes it will be abbreviated as MBTUH. Theoretically, this is the maximum capacity for cooling or heat output that the system will be able to produce. However, you should always take into account system losses. This means that the actual heat and cooling capacity to be delivered into a room or a building might be lower because of the distribution system losses. As a rule, the output BTUH will always be smaller than the input BTUH since the heating system will never be able to work at one hundred percent efficiency.

MBtu is described as one thousand BTU. Other common abbreviations include mBtu, MMBtu or mmBtu. The “M” is presumed to stand for the Roman numeral system, where this letter signified one thousand. In this context, MMBtu would be rendered incorrect, since it would stand for two thousands. However, MBtu is also mistaken for the SI “M” prefix that stands for multiplication with one million, while mBtu is mistaken for the SI “m” that denotes division by one thousand. Some companies are using “therm” to describe 100,000 BTU, while other use BtuE6 to avoid any confusions between 10,000 BTU and 1,000,000 BTU.

BTU conversions

Thankfully, there are plenty of online calculators to help us out with converting BTU to watts, watts to BTU, BTU to tons and BTU to kwh. If you want to take the task in your hands, you won’t have any trouble finding the specifications for each measuring unit. For example, one watt is the equivalent of 3.4121 BTU per hour. Likewise, one BTU per hour convers to 0.29307 watts.

BTUs and gas grills

All gas grills available on the market will have a maximum British thermal unit per hour. A gas grill that advertises 35,000 Btu translates to a device that produces that amount of Btu with all its burners in an hour. The gas grill in our example will use approximately two pounds of propane in an hour. However, don’t rely solely on the BTU rating advertised by a gas grill to form an opinion about how much heat it will produce. The rough estimation regards its heat output and only lets you know how much fuel it will consume.

If you’ve been thinking that the BTU number of a gas grill is a clear indicator of its power, you couldn’t be more wrong. Up until now, the ideal gas grill was supposed to produce roughly 100 BTU for every square inch. But now we know we should be paying attention to different factors to guesstimate the efficiency and power of a gas grill. It rarely matters how much fuel a grill will use up. In order to determine the heat output, you should also factor in the design, materials and size of the gas grill.

If the grill is light weight and its overall efficiency is not satisfactory, it will need a higher BTU output to cook food in a reasonable amount of time. However, infrared grills won’t require a large number of BTUs per square inch. Since their build is impressive and the heat from the burners is converted into radiant energy, they are more efficient. Gas grills that boast unrealistic BTUs per square inch are probably hiding a flimsy build.

Calculating BTU per square foot

In order to choose the right heating or cooling systems for a house or a building, you first have to figure out what the required BTU per square foot is. To do this, you will have to calculate the space that needs to be cooled or heated, which will help you in your hunt for the perfect air conditioning or furnace. You can use a BTU calculator or go for the DIY method that we’ll explain step by step below.

The first step implies measuring the square footage in every room within the house that will be heated or cooled. If you have a rectangular room, you will have to measure the length and the width in feet and multiply the two. Triangular rooms call for multiplying the width and the length and then dividing it by two. Circular rooms are a bit trickier, since you first have to determine the radius, which is the line segment from the center of the room to the edge. After that, you can multiply 3.14 by r². Rooms that have odd shapes are even harder to deal with. The simplest way is to split it into smaller sections and take each piece at a time.
If you read the specifications of an air conditioning or furnace, you’ll notice their capacity is determined by BTU per hour. The easiest way to determine the required cooling or heating capacity is to take as a reference 20 BTU per hour for square foot and multiply it by your room’s square footage. However, you should take note that this will not include the insulation your rooms have or the climate.

Air conditioning and BTU

The great majority of air conditioning units on the market express their capacity in BTU. When we’re talking about heating, a ton is the equivalent of 12,000 BTU. The rough estimates that people usually take as guideline are 30 BTU for square foot. To illustrate this, consider that a 2,000 square foot house will need a 5 ton air conditioning unit, which translates to 60,000 BTU. Another factor steps in: the EER stands for energy efficiency rating. This is easily calculated by dividing the BTU of an air conditioning unit to its wattage. To calculate the energy efficiency rating of a 10,000 BTU air conditioning unit that needs 1,200 watts, we divide 10,000 by 1,2000, which gives us the EER, 8.3. Knowing this number and guesstimating how much you will use your air conditioning unit during the summer, you can add up the numbers and see if an AC unit is worth the investment or not.

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Everything You Need to Know about Central Air Installation

November 6, 2015 by itadmin Leave a Comment

Central air installation is making its way into every household. And it’s no wonder, since no one likes sweating in the summertime. No longer a luxury, air conditioning units are a must, in areas where summer temperatures spike and the nights are unbearable. New models are becoming more efficient, quieter and cheaper. With all this in mind, it’s difficult to say no to central air conditioning installation. Thorough research on the internet and time spent reading reviews will help you decide what the best air conditioning for your home is, and it will shed some light on the steps you have to go through. But the ultimate question is “how much to install central air?”

The ABCs of central air

There is something you should do before drafting up a budget, starting to save money for the investment, and even before you ask around “how much does it cost to install central air?” Read all about the basics and know exactly what you need for your house. There is a significant difference between an air conditioning unit that can cool down 200 square feet and a central air installation that can handle a couple thousand feet. Narrow down your search and focus on an installation that will be able to cope with the square footage of your home. But don’t go overboard. While buying a central air installation is a sensible investment, don’t fall into the trap of buying more than you need.

An air conditioning that is too big will be difficult to handle, uncomfortable to set-up and more expensive. You might also want to get familiar with specific air conditioning terms. For example, tons are used to measure the output of an air conditioning unit. The higher the number, the more heat the installation will be able to remove from your house within an hour. If you’re looking for a central air conditioner installation that meets the expectations of a home measuring 1,500 square feet, look at units that are around 2.5 tons. But there are other factors to consider, besides central air installation cost. The rooms on the second and third floor are bound to become hotter during summertime than the basement. To make sure you factor in all the variables, you might want to hire an air conditioning contractor, who will help you make the right choice to suit both your home and your budget.

Cost to install central air

You might be tempted to keep an eye on sales and seize an air conditioner deal from a local wholesaler. This could bring down the central air installation cost, but you’ll need some expertise in order to make sure the installation job is done properly. We recommend you leave the whole process to professionals who’ll ensure that the job is done flawlessly and there are no faulty parts within the installation. If you’ve just moved into a new house or apartment that has never had air conditioning before, you’ll find there is an entire list of things to take care of. This is where a HVAC contractor will come in handy. The air conditioning installation will require additional breakers in the electrical panel, as well as wires within the foundation. You’ll also need a separate duct connected to the HVAC unit. An experimented air conditioner contractor will be able to give you an accurate estimate on the cost of installing central air in your home. Be prepared to pay anywhere between $3,000 for the cheapest models and $5,000 for a two ton unit. The latest systems can set you back by up to $10,000 if you are interested in top notch quality and an extended warranty.

Additional costs

There are a few things that could spike the price of your central air installation. If the design of your house is tricky, it might require additional duct work, which is bound to increase the total cost of the investment. Likewise, if you’re in need of a new thermostat, get ready to add that expense to the list of additional costs. If you don’t want to put up with a noisy air conditioning unit, there are ways to reduce the noise levels and make sure air conditioning doesn’t keep you up all night. Most units run at around 75 decibels, which translates to a noise that is loud enough to be heard through a window. Recent air conditioning models come with an implemented noise reduction feature. However, this doesn’t come cheap. If you decide to invest in a durable installation, expect to pay more for extra options that will keep you comfortable and happy on hot days.

How it works

A central air conditioner installation works in the same way a refrigerator does, only on a bigger scale. Employing chemicals that change their state from gas to liquids over and over again, the heat within a house is sucked out and replaced with cooler air. An air conditioner comprises an evaporator, which is part of a furnace, a compressor and a condenser, which are on the outside. When the compressor receives low pressure gas, the fluid is squeezed and it exits as a high pressure gas. As the fluid passes through the condenser, it cools down and shifts to a high pressure liquid. This goes on to pass through the evaporator, and, as its pressure drops, it transforms into a gas. The evaporating process draws out the heat within the room. When the fluid goes through the evaporator as a low pressure gas, it returns to the compressor to restart the process again. The fan that is attached to the evaporator is in charge with circulating the air within the rooms of a house. Since hot air is lighter, it rises above cooler air to be sucked into the central air unit.

Troubleshooting

After spending time on tackling the issue of how to install central air, and after investing in extra features, air conditioner maintenance will be minimum. However, you might deal with various issues like leaks or poor airflow over the years. Before you rush to the phone to schedule a service check-up, there are some steps you can perform to try to fix the problem yourself. These are the most common issues that tend to pop up over time.

Air conditioning not working at all

If you’re taken by surprise by your central air conditioning that has stopped working, you should first head to the thermostat and check if it’s working properly. If there’s nothing wrong with the thermostat, try checking the following:

Head over to the electrical panel and look for any tripped circuit breakers or blown fuses. Resetting them should solve the problem and restore your air conditioning to proper functioning.
Check to make sure the furnace power switch is on. You will find a power button on the outdoor unit.
Switch off the central air conditioning’s power and replace the batteries on your thermostat. Wait five minutes before giving the unit another try.

The central air unit is not cooling properly

If your air conditioning is working but it’s doing a poor job, there are some steps you can perform to locate the issue.

The first thing you should check is the filter. A clogged panel will most likely obstruct the air from flowing into the room, leading to poor cooling. Filters should be cleaned or replaced on a regular basis in order to avoid damage to the other parts of the air conditioning unit.
If the coils are surrounded by ice, you can close the unit, switch it back on and turn on the fan. You should notice the ice melting in a couple of hours.
Since they suck out all the moisture from the air, central air conditioners are bound to produce a lot of water. The drain pipe that is supposed to evacuate the water can get blocked, resulting in the air conditioning breaking down and creating a puddle on your floor. Cleaning the drain will take care of the issue.

Unusual noise coming from the A/C

If you start noticing a strange sound coming from your central air unit, it’s probably produced by a faulty or worn out belt. Generally, the belt that links the motor to the slips of the blower slips and needs to be replaced. A grinding sound coming from the blower usually points towards a motor problem. For this, you might want to call a professional service person. A rattling noise from the furnace might indicate that the panels are not tightly screwed on.

Air conditioning maintenance and guidelines

You might be tempted to neglect periodical maintenance for your central air unit. But if you want your investment and efforts to pay off, keep this check-list in mind so you can strike the perfect balance between cost efficiency and performance levels.

Air conditioning filters are often neglected and forgotten. Regularly replacing and cleaning your central air filters will improve the unit’s efficiency and increase its longevity. Filters do not only keep your air clean, they also keep the essential parts of the system dirt free.
Air conditioning coils are bound to clog and collect dirt over the years. An obstructed coil will lead to poor airflow and decrease the performance of your air conditioner. You should periodically clean the area surrounding the condenser unit and remove falling leaves and other debris that could clog the coils.
The condensate drains play a major role in the well-functioning of your central air unit. To keep them clean and dirt free, take a wire and pass it through the drains to clear out any debris. This way, your system will be able to prevent excess humidity that could produce condensation and affect the walls and woodwork in your house.

When looking for a suitable central air installation, you have to ask more questions than the classic how much does central air cost? You should take into account the square footage of your home, employ a seasoned HVAC contractor and also get ready to pay for extra options that will ensure you’re comfortable during the oncoming hot summer months. Latest air conditioner models come with top of the line features, but maintenance is a requirement that shouldn’t be neglected or postponed.

Image sources: 1, 2, 3.

How To MaKe Your Own Air Conditioner

October 19, 2014 by HVAC Expert Leave a Comment

Home Made A/C- How To Video

Do It YourSelf WebSites

August 15, 2014 by HVAC Expert Leave a Comment

Online Sites for HVAC Do-It-Yourselfers
A Review
By Betty Stephens

Need help in getting started on a Do-It-Yourself HVAC project? Here are some links to resources that may help you out.

Ductworks: The Original On-Line DIY Heating & Cooling – A Help site for Do-It-Yourself homeowners and builders to set them save money by offering initial help when they cannot find what they are looking for. May call or fill out a “Contact Us” form and they will find it for you. They are providers of HVAC products
https://www.ductworks.net/

Mold in HVAC System – Mold Removal Guide | Air Conditioner
removemoldguide.com/do-it-yourself/remove-mold-in-air-conditioning.
You are guided through the steps for your DIY air conditioner mold removal project.
www.central-air-conditioner-and-refrigeration.com/central_air_condition
o

HVAC Parts: If you’re not, changing the filter once a month, it will help. You’ll be … You may read this “Fix It Yourself or Do It Yourself” material online and it sounds great. You try it … You won’t find any professional hvac site that will teach how to installs it.
http://http://www.hvacpartsoutlet.com/

Need assistance finding your furnace or air conditioner parts? This site caters to do it yourself (DIY) homeowners and handymen, as well as HVAC Help Desk. McAfee SECURE sites help keep you safe from identity theft, credit card fraud..
www.doityourself.com/

Website and internet advice for HVAC businesses: Office manager or unlucky ones that been told to “get us on the internet” or “fix than website! A couple of great do-it-yourself website software), goal is to cut through the noise and demystify the online marketplace, and to help you achieve a better understanding.
www.energystar.gov

HVAC Maintenance Tips • For Home Improvement Homeowners choose to take on duct sealing as a do-it-yourself project. Do-It-Yourself Air Conditioning Repair – YouTube
www.youtube.com/watch?v=KCGpX2ru2Xc

Denver, CO Plumbing & HVAC Parts Department:
http://www.bellplumbing.com/denver-remodeling/plumbing-parts-departme

Do it yourself plumbing and HVAC projects in the Denver area: If an exact replacement is no longer available, we’ll help you find the best HVAC Training Videos, Watch and learn how to do hvac.
www.hvac-for-beginners.com/hvac-training-videos.html

Do It Yourself Geothermal Installations:
www.geothermalgenius.org/…/diy-geo-do-it-yourself-geothermal-installa

Web site for HVAC Repair Beginners. If you are having problems with your heating or cooling system, you should be able to find most of the common problems by using the air conditioner, furnace, heat pump, or boiler troubleshooting.
http://www.hvac-for-beginners.com/

Do-it-Yourself Heating, Air Conditioning, and Ventilation: Contact for all of your do-it-yourself heating, air-conditioning, and ventilating needs.
http://dalehuberco.com/

HVAC Installation: Doing a home HVAC installation is rather straight forward. Do it yourself what you may think will be the easiest part of a home HVAC installation is probably is not.
www.doityourself.com/stry/hvac-installation

Ductwork Design Services and heating & cooling products for the Do-It-Yourself homeowner. The design services start at $275 and include a Free Step-by-Step Ductwork Installation DVD with each design package. Half of your design fees can be applied to the purchase of your complete HVAC system.
https://www.ductworks.net/

RV A/C

August 15, 2014 by HVAC Expert Leave a Comment

Natural Gas Versus Propane A/C Cooling Units for RV’s
By Betty Stephens

If you drive an RV in the summer you know the heat can be a problem. The built in HVAC for the cab does not seem to be strong enough to cool the entire RV, so when you’re driving in extreme heat it may be necessary to run the generator to power the living area A/C to cool down the RV. There may be times in the summer that is may be necessary to have two A/C units running to cool RV (cab and living area AC).
To rapidly cool the living area on hot days try closing all the vents in the bedroom, opening the vents on the front A/C along with all the vents in the living area, shut the door to the back area of the RV and turn up both A/C units. Having the rear vents closed forces most of the cold air into the front part of the RV and helps cool it down.
Recreational vehicles normally have an air conditioner vents located on the rooftop. The location of the air conditioner means excellent cooling power and it can work well even when you are driving on the highway. Air conditioners in RV’s work like a typical refrigerator does. It does not cool the room down, instead it removes the heat. It takes the heat from the RV and dispose of it outside.
Parts of the Air Conditioner
An air conditioner has eight main parts: a compressor, condenser, evaporator, wires that
connect the parts together, an air moving system, a fan to push the air over the
condenser and another fan to push air over the evaporator. It also contains liquid for
cooling.

The RV’s AC compressor performs the job of circulating the Freon through the condenser and evaporator coils cooling fins and the cycle is repeated as the thermostat setting determines it necessary. Both the compressor and the fan motor use capacitors to provide a high voltage charge to get them moving and a lesser charge to keep them running. Only one capacitor is usually used for both fan and compressor. It the capacitor goes bad, neither the fan nor the compressor will start.
Energy Source
The air conditioner runs on what is known as AC power. The AC power is derived from a 120 volt socket that is plugged into a generator or a home. A gas generator burns a gallon of gas every hour and may be costly. It is a wise idea to use another power source such as a home or a generator that does not use gasoline.

The Compressor
Compressors condense the refrigerant vapors and heat it up as it condenses it. Then it moves to the condenser where the heat is taken out by the fan. This makes the vapor cool and becomes a liquid. The liquid slides down the capillary tubes and on to the evaporator. The liquid begins to soak up the heat from the air in the RV as it moves along it by the evaporators fan. This makes the liquid expand and when the liquid has soaked up enough of the RV’s heat, it becomes a vapor once again. This overly heated vapor is sucked by the suction the compressor creates and the cycle repeats itself.

Propane Cooling Unit
Propane is a liquefied petroleum gas, used in RVs for heating, cooking and refrigeration. It may be called bottle gas, referring to how it is sold and stored. Propane offers the RV owner these advantages:
1. Liquid propane is more readily available than gas in a power outage as gas stations may also lose power causing the pumps from working.
2. Liquid propane can be stored indefinitely whereas gasoline tends to go off after a few months.
3. Liquid propane is a clean burning fuel and the propane generator produces less emissions than a gasoline or diesel powered generator.
(LP Gas – Propane; abbreviation for liquefied petroleum gas, which is a gas liquefied by compression, consisting of flammable hydrocarbons and obtained as a by-product from the refining of petroleum or natural gas. It is also called bottled gas, LPG (liquid petroleum gas) and CPG (compressed petroleum gas).
Natural Gas Cooling Unit
A gas cooling unit uses ammonia as the coolant, and water, ammonia and hydrogen gas to create a continuous cycle for the ammonia.
It works like this:
Heat is applied to the ammonia and water solution in the generator. As the mixture reaches the boiling point of ammonia, it flows into the separator. Ammonia gas flows upward into the condenser, dissipates heat and converts back to a liquid. The liquid ammonia makes its way to the evaporator where it mixes with hydrogen gas and evaporates, producing cold temperatures. The ammonia and hydrogen gases flow to the absorber where the water collected in the separator in step No. 2 mixes with the ammonia and hydrogen gases. The ammonia forms a solution with the water and releases the hydrogen gas, which flows back to the evaporator. The ammonia and water solution flows toward the generator to repeat the cycle.

Ceiling Fans

August 15, 2014 by HVAC Expert Leave a Comment

DO CEILING FANS HELP LOWER ELECTRIC AND A/C BILLS?
By Betty Stephens

Ceiling fans can cut back excessive use of your home’s air conditioning and heating unit and use 5% less energy. They use about the same energy as a 100-watt light bulb.
The Department of Energy says YES. The Department of Energy’s Energy Information Administration predicts that the price for natural gas, used for electricity and heating fuels, may increase 65 percent this winter .So, it is time to start thinking about ways to save on heating and cooling, especially since it makes up 45 percent of an energy costs. The answer to saving money is with a ceiling fan.
Turn on Fans
Fans make a room feel cooler, and the one in our living room quit w Turn up your thermostat because a ceiling fan can make an air-conditioned room feel four degrees cooler.

Savings with a Fan
The ceiling fan works to move the air throughout the room, which makes cooler. If you use a ceiling fan in cooler climates, it can actually make a house feel cool enough to prevent the need for an air conditioning. In hotter climates, a ceiling fan can make an air-conditioned room feel four degrees cooler, allowing you to raise the thermostat. By raising it two degrees, you can save up to 14 percent on your yearly energy bill.
Always turn off the fan when no one is in the room. Ceiling fans make people feel cooler, but they won’t actually change the temperature of a room like an air conditioning unit would. So there’s no point in burning the energy used by a fan when the room is empty.
Using the Fan
A ceiling fan should rotate counter-clockwise (in summer time), which moves the airflow in a downward direction creating a cool, wind-chill effect. When the fan is rotating clockwise, change its direction by just flipping the fan’s slide switch, is found on the motor housing at the body of the fan. In cooler weather change it back and the fan can make a room feel warmer. When a fan is rotating in a clockwise direction, it forces warm air down from the top of a room to the bottom.
Choosing the Right Fan
The height of the ceiling determines the fan you should choose. There should be at least seven (7) feet between the floor and the blades of the fan. This height prevents people from hitting their head. Buy a fan with a rod that allows the fan to have a hanging depth (the distance between the ceiling and the bottom of the fan) of about 10 inches, this allows the air to circulate (If there’s enough room.).
Fans with a performance grade motor are expensive but are designed for lots of use, operating 12 or more hours a day. A medium grade motor can be used for 12 hours or less a day, and a moderate or economy grade fan can be run for eight hours or less a day.
Summary
In the summer, cooling your home can account for half of your summer power use. Central Air Conditioning comfort comes with a hefty price. A 2.5-ton central system uses about 3500 watts. At 12 cents per kilowatt hour, it costs 42 cents an hour to run your air conditioning unit multiplied over 24 hours, It is a $10 a day expense. Over the course of a month, summer can cost your family $300 or more in extra electricity costs. So run your fans. A ceiling fan can cost around a penny an hour to run. You can run more than 40 ceiling fans for the same cost of your central AC.

Heating & Cooling A Submarine

July 29, 2014 by HVAC Expert Leave a Comment

Heating, Cooling Submarines
By Betty Stephens

Heating Submarines
A submarine is mostly all metal, and metal is an excellent conductor of heat. The surface area of a submarine is large. The ocean is filled with convection currents, caused by the sub’s motion. This makes the heat transfer between submarine and ocean an active process. The temperature’s difference between the sub and the ocean is small, the total heat transfer is considerable because of the large contact area.
There is continuous production of heat, given off to the submarine air by hot engines, storage batteries, galley stove, electric lights, electric heaters, other devices, and human passengers. There is continuous production of moisture, given off to the air by evaporation from these same four main sources. The moisture production averages about 1000 pounds of water per day.
If the submarine is running on the surface, it is an easy matter to discharge this excess heat and moisture outboard. When the submarine is submerged, heat cannot be discharged outboard, and must be eliminated during recirculation of the air.
If the submarine is warmer than the ocean water, the interior heat of the vessel gradually passes through the shell into the water. The temperature of the air inside drops and, when it reaches the dew point, the water vapor in the air begins to condense on every available surface. So, the interior surfaces of a submarine are coated, with cork paint, to prevent or reduce this condensation to a minimum. The beginning of the condensation, however, depends upon the dew point, and this can be controlled by air-conditioning. Therefore, air-conditioning is just as essential for this purpose as for the comfort of the crew. It is always advisable to lower the dew point before a dive.
But, if the ocean is warmer than the submarine, there is a passage of heat from the water into the ship. However small this may be, it adds to the interior heat. The same result occurs if the loss of heat from this vessel to the ocean is less than the interior heat production. In hot summer weather, especially in tropical and subtropical regions, the air temperature in a submarine may rise to fairly high levels.
Air Conditioning the Submarine
In a submarine, there is only a few cubic feet of space available for air-conditioning equipment, and the cooling capacity is limited. The purpose of the air-conditioning system is not to cool the whole submarine. Let’s assume the air contains enough oxygen for the needs of all the occupants within the given space. A supply of oxygen compressed in cylinders is carried on board submarines to be released into the air as needed.

The submarine has room enough for air-conditioning machinery to control the dew point. Control of the dew point means control of the relative humidity, and the relative humidity is the factor of major importance.
Lowering the Dew Point.
The dew point of the air is the temperature at which that air is saturated with moisture. If the temperature of the air is then further lowered, some of the moisture must condense out.
The air in the submarine room is drawn by fans into and through the ducts to the air-conditioning evaporator. In passing over the cooling coils, its temperature drops below its dew point and part of its water vapor condenses out, inside the evaporation cabinet. The condensed water is not permitted to get back into the air, but is drained off into a tank. The air, now lower in moisture content and slightly lower in temperature also, continues its flow through the ducts and is finally blown out into the room again. This conditioned air mixes with the moisture and warmer air still in the room, resulting in an over-all condition that is drier than the original unconditioned air.
Air-conditioning in the tropics.
In hot climates, the air-conditioning system must be operated at maximum capacity. The procedure is to operate the compressors at full speed and the blowers at a speed that the temperature of the air from the discharge side of the evaporators is below the dew point. The conditions of high air temperature in the tropics are naturally adverse to effective air-conditioning, especially when the large area of open water surfaces in the bilges is considered. The plant must be run to obtain maximum comfort and protection of equipment against moisture, both of which are obtained by removing the large quantity of water vapor from the air. This condensing process is accomplished by always maintaining the temperature of the discharge air from the evaporators below the dew point.
Nuclear Submarines
The nuclear submarine, USS Sea Wolf was the only U.S. submarine to have a sodium-cooled nuclear power plant. It was commissioned in 1957, but it had leaks in its super heaters, which were bypassed. In order to standardize the reactors in the fleet, the submarine’s sodium-cooled reactor was removed starting in 1958 and replaced with a pressurized water reactor.

A liquid metal cooled nuclear reactor, liquid metal fast reactor or LMFR is an advanced type of nuclear reactor where the primary coolant is a liquid metal. Liquid metal cooled reactors were first adapted for nuclear submarine use but have also been extensively studied for power generation applications. They have safety advantages because the reactor doesn’t need to be kept under pressure, and they allow a much higher power density than traditional coolants.

Cooling Glass Sun Rooms

July 28, 2014 by HVAC Expert Leave a Comment

Sunrooms – Heating and Cooling
By Betty Stephens

Sunroom
This room may be called a solarium or conservatory. It is usually a glassed-in living space typically attached to the house and accessible from indoors designed to function as additional living area during mild weather but may be too hot or cold in the heart of summer or winter.

When a homeowner decides on a four season sunroom, the space must have a heating and cooling system. A space with most of the walls being windows needs proper temperature control. A four season sunroom should be comfortable all year long, even in the coldest winter months and hottest summer months. Since most homeowners already have central air conditioning in their home the sunroom can tap into the existing system. This is done by bringing ductwork into the sunroom and installing vents. The method is easy to keep the temperature of the room consistent with the rest of the house. A separate thermostat can also be installed and the sunroom’s temperature can be adjusted without affecting the rest of the house.
Need for Heating and Cooling
Since the need for heating and cooling is so variable throughout the year and even throughout the course of a day, independent temperature control in a room of this type is critical. If the thermostat that controls the home HVAC system is in the middle of the rest of the house and it is a mild, sunny day, the system will have very few calls for heating or cooling but the sunroom could be baking hot and will stay that way until the sun goes down.

Mini-split AC Units
While using existing ductwork is a very effective way to heat/cool a four season room, sometimes it is not an option. This method can be more difficult (and more costly) if the home is built on a concrete slab. There is another option for the homeowner is a mini-split air conditioning unit. They are slim and compact, wall-mounted systems. Mini-splits are usually installed high on a wall so that they are not at eye level, even though these units look quite stylish. The compressor is located outside of the sunroom with the tubing running behind the walls, completely out of site.

A mini-split it is a split system like most central air systems found in homes, with an inside air handler/evaporator unit and an outdoor condenser/compressor unit that are connected by refrigerant, power, and communications lines. One difference is it doesn’t use ductwork to distribute the air, but rather the wall mounted indoor unit handles moving the air. While these units can also be used to heat and cool an entire home very effectively, they’re almost tailor made for sunrooms. They are quiet, efficient, and powerful. These units are completely independent from the central HVAC system and as such can either keep the room perfectly comfortable or be completely switched off if the room isn’t used. They come in a range of options from cooling only non-inverter compressor units to hyper-heat high output heat pumps with an inverter compressor that is able to vary its output to match the exact need of the room.

Other Options
Other options for heating and cooling is using a PTAC unit (called a Hotel unit) which is similar to what is seen in hotel rooms, or a portable air conditioning units. Homeowners can have radiant floor heating or base board heating installed. However, they only heat the sunroom and won’t provide a cooling mechanism.

Location of Sunroom
Deciding the best location for the sunroom room is the first step when planning a glass or screen addition. In northern climates, a southern exposure is best because it receives the most light each day.

In the South, a southern exposure means additional cooling is necessary, which could be costly.

An eastern exposure eases cooling by providing sun in the morning and shade the rest of the day, but not so great for after work.

A western exposure will expose you to harsh afternoon sun that needs to be shaded.

A northern exposure provides lower levels of light and partial shade most of the day. In the North, this can cause the room to be too cool and damp, but it can work fine in the South.

Thomas Midgley Jr. – Inventor of Refrigerant

July 23, 2014 by HVAC Expert Leave a Comment

Thomas Midgley, Jr
By Betty Stephens

Inventor of Freon and Leaded Gas
Thomas Midgley, Jr. (May 18, 1889 to November 2, 1944) was an American mechanical engineer and chemist. He was a key figure in a team of chemists, led by Charles F. Kettering, that developed the tetraethyl lead (TEL) additive to gasoline as well as some of the first chlorofluorocarbons (CFCs). He was granted over a hundred patents. He was honored for his scientific contributions during his lifetime but, the negative environmental impact of some of his innovations has tarnished his legacy.
Midgley was born in Beaver Falls, Pennsylvania. His father was also an inventor. He grew up in Columbus, Ohio, and graduated from Cornell University in 1911 with a degree in mechanical engineering.
He started work at General Motors in 1916. In December 1921, while working under the direction of Kettering at Dayton Research Laboratories, a subsidiary of General Motors, He discovered that the addition of TEL to gasoline prevented “knocking” in internal combustion engines. The company named the substance “Ethyl”, avoiding all mention of lead in reports and advertising.

Oil companies and automobile manufacturers, especially General Motors which owned the patent jointly filed by Kettering and Midgley, promoted the TEL additive as a superior alternative to ethanol or ethanol-blended fuels. December 1922, the American Chemical Society awarded Midgley the 1923 Nichols Medal for the “Use of Anti-Knock Compounds in Motor Fuels”.

Lead Poison
In 1923, Midgley took a time off to cure himself of lead poisoning. “After about a year’s work in organic lead,” he wrote in January 1923, “I find that my lungs have been affected and that it is necessary to drop all work and get a large supply of fresh air.” He went to Miami, Florida for vacation.

Freon
In the 1920s, air conditioning and refrigeration systems employed compounds such as ammonia (NH3), chloromethane (CH3Cl), propane, and sulfur dioxide (SO2) as refrigerants. These were toxic, flammable or explosive and, in the event of leakage, could result in serious illness, injury or even death. The Frigidaire division of General Motors, at that time a leading manufacturer of such systems, sought a non-toxic, non-flammable alternative to these refrigerants Kettering, the vice president of General Motors Research Corporation at that time, assembled a team that included Midgley and Albert L. Henne to develop such a compound.

The team soon narrowed their focus to alkyl halides (the combination of carbon chains and halogens), which were known to be highly volatile and also chemically inert. They eventually settled on the concept of incorporating fluorine into a hydrocarbon. They rejected the assumption that such compounds would be toxic, believing that the stability of the carbon fluorine bond would be sufficient to prevent the release of hydrogen fluoride or other potential breakdown products. The team eventually synthesized dichlorodifluoromethane, the first chlorofluorocarbon (CFC), which they named “Freon”. This compound is more commonly referred to today as “Freon 12”, or “R 12”.

Freon and other CFCs soon replaced the various toxic or explosive substances previously used as refrigerants, and were later used in other applications, such as propellants in aerosol spray cans and asthma inhalers. The Society of Chemical Industry awarded Midgley the Perkin Medal in 1937 for this work.

His Legacy
In 1940, at the age of 51, Midgley contracted polio, leaving him disabled. This led him to devise an elaborate system of strings and pulleys to help lift him out of bed. This system was the cause of his death when he was entangled in the ropes of this device and died of strangulation at the age of 55.

Midgley died three decades before the ozone-depleting effects of CFCs in the atmosphere became widely known. Another adverse effect of Midgley’s work was the release of large quantities of lead into the atmosphere as a result of the large-scale combustion of leaded gasoline all over the world.

Thomas Midgley, Jr