Air changes per hour Bake-out Building envelope Convection Dilution Domestic energy consumption Enthalpy Fluid dynamics Gas compressor Heat pump and refrigeration cycle Heat transfer Humidity Infiltration Latent heat Noise control Outgassing Particulates Psychrometrics Sensible heat Stack effect Thermal comfort Thermal destratification Thermal mass Thermodynamics Vapour pressure of water
The Refrigeration Loop is a closed system and refrigerant should never have to be added to the unit unless there is a leak. Most residential units use R-22/R410A refrigerant. Prices of R-22/R410A are rising every year as we get closer to the date when refrigerant manufacturers will no longer be able to make R-22/R410A. Phase-out of R-22, an HCFC, begins in 2010 and expected to be complete by 2020.). Furthermore, make sure you ask what the service company charges for R-22 when you are calling an HVAC contractor.
It can be hard to make the decision to replace or repair your AC unit. However, in many cases, homeowners call in HVAC professionals to check their units and provide a second opinion. A technician can tell you if there’s plenty of life left in your old air conditioning unit or that it’s time to let it go and get a new one. Your HVAC technician may check out your home’s insulation quality, too. You could increase your system’s effectiveness by improving the insulation.
If you have an older central air conditioner, you might choose to replace the outdoor compressor with a modern, high-efficiency unit. If you do so, consult a local heating and cooling contractor to assure that the new compressor is properly matched to the indoor unit. However, considering recent changes in refrigerants and air conditioning designs, it might be wiser to replace the entire system.
Low refrigerant charges take away from the life of the compressor. The compressor is cooled from the return refrigerant vapor. When there is a low charge there are fewer vapors to cool the compressor, therefore it runs hotter. Any compressor (or electric motor for that matter) which runs above the recommended temperature range will have a shorter life span and cost more to operate.
Consequently, this water must exit the air handler—typically through plastic pipe or a drain tube. That drain tube goes directly outside, often terminating near the compressor, or to a floor drain or to a small electric “condensate pump” located by the air handler. Where a condensate pump is used, it connects to a 1/2-inch vinyl or rubber tube that exits outdoors or to a drain.
Heaters exist for various types of fuel, including solid fuels, liquids, and gases. Another type of heat source is electricity, normally heating ribbons composed of high resistance wire (see Nichrome). This principle is also used for baseboard heaters and portable heaters. Electrical heaters are often used as backup or supplemental heat for heat pump systems.