Remove heat from an enclosed region. Refrigerant, compressor, expansion valve (flow control device), evaporator, condenser, pipes and tubes. EXPLANATION OF HOW IT WORKS/ IS USED: Refrigerant flows through the compressor, which raises the pressure ofNext the refrigerant flows through the condenser, where it condenses from vapor form to liquid form, giving off heat in the process. The heat given off is what makes the condenser "hot to the touch." After the condenser, the refrigerant goes through the expansion valve, where it experiences a pressure drop. refrigerant goes to the evaporator. The refrigerant draws heat from the evaporator which causes the regrigerant to vaporize. The evaporator draws heat from the region that is toThe vaporized refrigerant goes back to the compressor to restart the cycle. Compressor: Of the reciprocating, rotary, and centrifugal compressors, the most popular among domestic or smaller power commercial

refrigeration is the reciprocating. The reciprocating compressor is similar to anA piston is driven by a motor to "suck in" and compress the refrigerant in a cylinder. As the piston moves down into the cylinder (increasing the volume of the cylinder), it "sucks" the refrigerant from the evaporator. used ac units los angeles intake valve closes when the refrigerant pressure inside the cylinder reaches that of theamps for ac unit pressure in the evaporator. 3 ton ac package unitsWhen the piston hits the point of maximum downard displacement, it compresses the refrigerant on the upstroke. The refrigerant is pushed through the exhaust valve into the condenser. Both the intake and exhaust valves are designed so that the flow of the refrigerant only travels in one direction through the

Diagram of Compressor (Belt Driven In This Instance) Detail of Compressor Valve Components of Compresion Refrigeration In A Dorm Refrigerator condenser removes heat given off during the liquefication of vaporized refrigerant. is given off as the temperature drops to condensation temperature. (specifically the latent heat of condensation) is released as the refrigerant liquefies. There are air-cooled and water-cooled condensers, named for their condensing medium. more popular is the air-cooled condenser. The condensers consist of tubes with externalThe refrigerant is forced through the condenser. In order to remove as much heat as possible, the tubes are arranged to maximize surface area. Fans are often used to increase air flow by forcing air over the surfaces, thus increasing the condenser capability to Evaporator: This is the part of the refrigeration system that is doing the actual cooling. Because its function is to absorb heat into the

refrigeration system (from where you don't want it), the evaporator is placed in the area to be cooled. The refrigerant is let into and measured by a flow control device, and eventually released to the compressor. of finned tubes, which absorbs heat from the air blown through a coil by a fan. tubes are made of metals with high thermal conductivity to maximize heat transfer. refrigerant vaporizes from the heat it absorbs heat in the evaporator. Flow control device (expansion valve): This controls the flow of the liquid refrigerant into the evaporator. Control devices usually are thermostatic, meaning that they are responsive to the temperature of the refrigerant. All variables are in units of per unit mass. From stage 1 to stage 2, the enthalpy of the refrigerant stays approximately constant, thus From stage 2 to stage 3, heat is put into the system, thus qin = h3 – h2 = From stage 3 to stage 4, work is put into compressor, thus

work = h4 – h3. From stage 4 to stage 1, heat is given off through the condenser, thus qout = h4 – h1. The coefficient of performance describes the efficiency the evaporator to absorb heat in relation to the work put in, thus b = refrigeration effect / work input = qin / work = (h3 – h1) / (h4 – h3). Heat transfer depends on the properties of the refrigerant. refrigerants will obviously have different enthalpy values for a given state. with one specific refrigerant, the enthalpy values depend on the temperatures and pressures in the warm and cold regions. temperature affects how well the refrigeration system is able to cool the enclosed region. Clearly, if the outside temperature is very hot (i.e. much above room temperature), the system may not be as successful in lowering the temperature of the enclosed region as it would at room temperature. WHERE TO FIND COMPRESSION REFRIGERATION SYSTEMS: Moran, Michael J. and Shapiro, Hoaward N., Fundamentals of Engineering

Thermodynamics, New York: John Wiley & Sons, Inc., � 1992. Langley, Billy C., Refrigeration and Air Conditioning, Reston Virginia: Reston Publishing Company, Inc., � 1982.Home » Your Efficiency » Slow Your Roll Summer Energy Efficiency Q&A There's no doubt about it, Texas weather can go from mild to extreme in a minute, requiring us to take extra measures to keep our homes comfortable. However, there are many misconceptions when it comes to efficiency, and we want you to know how you can conserve and help reduce your monthly bill. It's all about slowing the roll of your meter. Click here to skip right to our Energy Efficiency Quick Tip Videos. Q: I live in an energy-efficient home and don't touch the thermostat, so how is it possible that my monthly bill could suddenly increase? A: Weather conditions--whether it's very cold or hot outside--are a significant contributor in just about every aspect of a home's electric usage. For example, weather can cause your AC/Heating system to work harder to achieve the warmer temperature setting we typically like to keep us comfortable when it's cold outside.

Your system will then cycle more often to maintain it. The opposite is true during summer, when it's very hot outside. Weather also affects our habits. We tend not to go outside as often, which leaves room for use of electronics such as games and television to pass the time. These types of things may sound minor, but they all add up to higher usage during days when it's very cold or hot outside. The length of time (hours) temperatures are low during winter (or high during summer)--and the number of consecutive days of low (or high temperatures)--also highly affect your home's electric consumption. Q: How does weather affect an AC/Heating system? A: When it's cold outside during winter, it takes a lot of energy to heat your home. For example, if you set your thermostat to the recommended temperature of 68 degrees, and it is 38 degrees outside, the difference in temperature is 30 degrees, which inevitably increases run time to maintain your level of comfort. (Every time an AC/Heating unit cycles or "kicks on," it uses a lot of energy.)

The same thing happens during hot summer days. Your AC system will work as hard as it can to lower your home’s temperature. Once it reaches your thermostat setting, your system will cycle to maintain it. This is an important area and the first one to pay close attention to, as it contributes up to fifty (50) percent of the typical home's monthly bill. Q: What is the most energy-efficient thermostat setting? A: GVEC recommends setting your thermostat at 68 degrees in winter and 78 degrees in summer. If this is uncomfortable for you, try lowering (or raising) the thermostat one degree at a time until you become accustomed to the setting. For every degree you raise your thermostat in summer or lower it in winter, you can expect to save about four to six percent on your heating and cooling costs. This can be impactful since nearly 50 percent of the typical home's energy bill is due to heating and cooling. Remember, the bigger the difference between the outside temperature and your thermostat setting, the harder your AC/Heating unit will have to work to close that difference.

That equates into higher usage. Q: Does it matter what kind of AC/Heating system I have in my home?An energy-efficient heat pump AC/Heating system uses less energy overall than a conventional system, and the higher your system's efficiency rating is (SEER), the more cooling and heating you'll get for your energy dollar. Heat pump units are especially efficient during colder months when consumers typically receive their highest energy bills. Q: Why are heat pump systems more efficient during colder months? A: Let's start with conventional systems. In heat mode, they use heat strips (resistance heat) to warm your home -- kind of like giant toasters. In comparison, heat pump systems use a reverse refrigerant system to heat your home. While they work just like a conventional system during summer to cool your home, when in heat mode, the refrigerant automatically reverses to pump ambient heat from the outside air into your home. You may not think there is enough heat outside to warm your home during the winter time, but there is!

Since heat pumps use electricity to move heat, rather than create it as heat strips do, they are extremely efficient. Heat pumps are considered to be 250% efficient as compared to the 100% efficiency of a conventional system. (You may think 100 percent is good, but that only means conventional systems use every watt of electricity to create heat.) When it becomes so cold outside that there is no longer sufficient heat in the air for heat pumps to work efficiently, they rely on backup heating: heat strips. The hope is that it doesn't stay that cold in our area for long, so your system can return to its more energy-efficient heat pump mode to heat your home. (By the way, when the auxiliary/emergency heat light is on, that means your unit has determined that it is too cold outside and is using heat strips for backup heat.) Q: What other things can affect the efficiency of my AC/Heating system? A: There are various factors that affect your AC/Heating efficiency: Q: Are there other ways weather can affect my usage?

A: There sure are. Most people do not realize the many factors that contribute to the total efficiency of their home such as: Your electric bill will almost never be the same as your neighbor's unless you have the same house, appliances, family, lifestyle and routine as them! Q: Does GVEC offer a way for me to monitor my usage? A: GVEC offers free energy management tools through our SmartHub self-service portal. Once you register to use SmartHub or download the free SmartHub app to your smartphone or tablet, you can view your usage. To do this, we recommend going to the "My Usage" tab and then selecting "Usage Explorer" from the dropdown menu. "Usage Explorer" allows you to view your energy usage by the hour, day or month along with the daily high and low temperatures. This is a great visual to notice the correlation between weather and usage. During winter, usage goes up as temperatures go down. During summer, usage goes up when temperatures go up. The data can also lead to other observations about your home's energy usage patterns when you view your usage by the hour or compare weekend usage with weekday usage.

Please note: it takes 48 hours for a day's usage data to appear. Q: I'd like to improve my home's energy efficiency. A: GVEC is here to help with an array of member services to help you make your home more energy efficient. Just call us at 800.223.4832 (GVEC). Have you signed up for SmartHub? To start using the app today, scan the QR code below matching your smartphone or tablet. The app is free! ____ I have my AC/Heating unit serviced twice a year by a professional during the April/May and October/November timeframe to be ready to withstand the upcoming summer and winter months. ____ I check my AC filters monthly and change them at least every 3 months (more often in high-use months like summer and winter). ____ During winter, I keep the AC at 68 degrees when at home, and lower it a few degrees when no one is home for 8 hours or more. During summer, I keep the AC at 78 degrees. ____ I use as little hot water as possible by taking shorter showers and baths and using cold water when washing clothes.

I’ve set the thermostat for my water heater at 120 degrees. ____ I've taught my family to turn off lights when no one is in the room and to limit the amount of times they open and close the refrigerator. I've also put my electronics on a power strip I can easily turn off when done. ____ I've set my pool or hot tub pump to work as minimally as possible. ____ I do not use space heaters on top of my central heating to warm my home during winter. I know these small appliances were only designed to provide temporary heat in a small space and if used regularly throughout the house, can greatly increase my electric bill. ____ I will not manually switch my heat pump to emergency heat. If I think my system isn't working properly, I'll call for service. Get more tips at www.energysavers.gov! Get a printable version of this checklist here! Watch our videos below for quick tips on how you can be more energy efficient today, and in the future. How to save on heating & cooling: