We are often asked about various component parts of an air conditioning system and do our best to explain to our customers why each part is so important to the system. Heat pumps are one important component of any air conditioning system but also have an added extra enabling cooling and heating, making them a versatile and welcome piece of electronics.

A heat pump is an air conditioner that contains a valve that lets you decide whether you want heat or cool air to circulate throughout your home. The heat pump valve can be adjusted based on your specific needs – providing you with a cool breeze or reversing its flow of Freon, located in the air conditioning refrigerant, and delivering warm air to the room.

Heat pumps are a cost-effective way to provide the very best in central air conditioning. Depending on climate and heating and air conditioning needs, the choice of heat pumps will vary in price. Less noisy components are usually more costly but deliver a quiet unobtrusive operation. A well-maintained heat pump system can last for years and allowing us to regularly maintain your air conditioning system and parts will mean efficient running too. Cleaning the air conditioning air filter at least once a month properly (some air conditioning systems now even have disposable air conditioning filters), having an annual air conditioning inspection with our air conditioning engineers and paying attention to the heat pump thermostat are all ways to make your heat pump air conditioner last.

If you are shopping around for a new heat pump thermostat, look for one that has a variety of features to deliver an overall performance that will give you the best in temperature control. There are two main types of heat pump thermostats and the options are based on preference. There are electro-mechanical and electronic heat pump thermostats, used for residential purposes. The electronic heat pump thermostats can provide any temperature and are entirely programmable, where you can set it to 60 degrees at night and then have it programmed to be at a comfortable 70 degrees when you wake up in the morning. Electro-mechanical thermostats contain a bi-metal coil or strip made of two different types of metals, which expand and contract at different rates. When this takes place, the coil or strip moves and connects to a device that will provide the electrical circuit. They are set at standard temperatures and you adjust them with a little switch to the appropriate temperature.

The heat pump clearly plays an important role to the air conditioning system whether this application is residential or commercial. Understanding this component is important for maintenance of your heating or cooling system. At Simply Air Conditioning London we are experienced in many different kinds of heat pumps and will be able to advise you on the one that is right for your application and provide a follow up maintenance plan to keep things efficient and delivering optimum performance for you.

Here is a simple explanation how an air conditioning system works and the major component parts. Often when you are considering purchasing air conditioning, it is difficult to know where to begin. We hope with our articles we are assisting you to gain knowledge and learn something more about equipment we take for granted yet these days could not live without if you consider the wider impact.

We have included heat pumps in this article too as combined systems are what many people opt for as they can have year round climate control. The function of each component is described:

• 1. An air conditioning or heat pump compressor compresses low-pressure refrigerant gas into a high pressure, high temperature gas. Usually the compressor is in the outdoor portion of an air conditioning or heat pump system.
• 2. The air conditioner or heat pump compressor unit is a high-pressure pump driven by an electric motor. The air conditioning compressor is packaged in the outdoor compressor/condenser unit.
• 3. A condenser or condensing unit is typically a condensing coil inside which high temperature high-pressure refrigerant gas flows, and over which a fan blows air to cool the refrigerant gas back to a liquid state (thus transferring heat from the refrigerant gas to the air being blown by the fan). The condenser unit is a coil of finned tubing and a fan to blow air across the coil. Usually the condenser unit is in the outdoor portion of an air conditioning system, often packaged along with the compressor motor discussed above.
• 4. The change of state of the refrigerant, from hot high-pressure gas to a liquid releases heat, including heat collected inside the building to the outside.
• 5. A metering device, which dispenses liquid refrigerant into an evaporator coil. The metering device may be simply a thin section of tubing (a capillary or “cap” tube). It may also be a more sophisticated thermostatic expansion valve (TEV) which includes a temperature sensing control that can open and shut the device against refrigerant flow.
• 6. An evaporator coil or cooling coil: Typically, the cooling coil is a section of finned tubing (it looks a lot like a car radiator) into which liquid refrigerant is metered and permitted to evaporate from liquid to gas state inside the coil. This state change of the refrigerant, from liquid to gas, absorbs heat, cooling the evaporator coil surface and thus cooling indoor air blown across the cooling coil. Usually the cooling coil is located inside the air handler.
• 7. An air handler and blower unit, which provides a fan to blow building air across or through the evaporator coil. The air handler blower fan unit moves building air across the evaporator coil surface in order to condition building air by cooling it (and thus also by removing moisture from the cooled air).
• 8. A duct system which distributes conditioned air from the air handler in to the occupied space (supply ducts), and which takes air from the occupied space and returns it to the cooling system air handler.

Heat Pump Systems use the same components described above, with the addition of a reversing valve that allows the system to run “backwards” in cold weather. Therefore, in air conditioning mode the heat pump is moving heat from inside the building to outdoors while in heating mode the heat pump is moving heat from outdoor air (or water in some designs) to the building interior.