- We will answer the question, “What is a metering device”. We will define the various types of metering devices and how they work.
- How the metering device is involved in the refrigeration cycle
- A comprehensive list of metering devices defining the metering devices commonly used in HVAC
- Lots of resource and related links to help you learn more about metering devices.
Evaporator Coil for Heat Pumps & Air Conditioners
Evaporator Coil for Heat Pumps & Air Conditioners – the evaporator is responsible for absorbing heat into the coils and the refrigerant. The evaporator is an essential component of vapor compression refrigeration. This is usually done as result of passing air or water over the evaporator coil where a heat exchange process takes place. Heat leaves the air or water (whatever medium is used) and is absorbed into the coil and the liquid refrigerant. As more and more heat is absorbed by the evaporator coil and the refrigerant again changes state from a liquid to a refrigerant vapor. By the time the refrigerant leaves the evaporator coil the refrigerant should be all vapor and ready to be received again by the refrigeration compressor. (more…)
The Condenser for Air Conditioners and Heat Pumps
The condenser coil receives the high pressure high temperature refrigerant vapor from the compressor and immediately begins to remove heat from the refrigerant vapor. As the refrigerant vapor makes its way through the condenser coil more and more heat is removed and the refrigerant vapor changes state from a refrigerant vapor to a refrigerant liquid. While the liquid refrigerant changes temperatures from a higher temperature to a slightly lower temperature the pressure remains constant. As the refrigerant vapor leaves the condenser coil it makes it way to the metering device. (more…)
The Compressor | HVAC Refrigeration
In a typical HVAC air conditioner or heat pump there are four major components that make the process of refrigeration work. Basically, this is how air conditioners work. And how heat pumps work. The first component in the process is a compressor or the heart of any air conditioner or heat pump system.
The Compressor | HVAC Refrigeration - How it Works
HVAC Refrigeration Compressor - A compressor receives the refrigerant vapor from the evaporator coil and compresses the refrigerant vapor. The vapor enters the refrigeration compressor at a low pressure and a low temperature and leaves the refrigeration compressor at a higher temperature and a higher pressure. The lower temperature refrigerant vapor is responsible for providing cooling for the refrigeration compressor and it also carries with it a small amount of oil which migrates from the compressor throughout the system. After the refrigerant vapor is compressed it is discharged to the condenser coil. A compressor is an essential component in the vapor compression process of refrigeration. (more…)
Fixing a Refrigerant Leak – You had the new air conditioner or heat pump system installed some years ago and suddenly it stopped heating or cooling properly so you call the HVAC contractor to check it out. The HVAC technician arrives and spends about thirty minutes HVAC troubleshooting and then he comes to you with the news. The unit needs a charge of refrigerant. It is low on refrigerant (R-22) or R-410A. You ask the HVAC technician if it is normal for this to occur and he informs that, no, it is not normal for the HVAC system to lose refrigerant that you have a refrigerant leak. (more…)
Duct Work and High Ceilings | HVAC Duct Work Systems
Duct Work and High Ceilings – I did not see any reference to my question and would appreciate a response as soon as possible, as due to medical situation, have to make a decision soon. We own an OLD house with 13′ ceilings in a large part of the home and 11″ ceilings in the LV/DR and BR. We are oscillating on where to place the ducts….Floor or ceiling. It appears to be counterproductive to me to put the duct work in the ceiling since it will have so far to go. We are looking for the most cost-effective, not upfront cost but operating cost, solution. In addition, we are considering DF heat pumps. The house will need 2 or 3 to be zoned correctly. Please let me know about the duct placement and thank you for your help? (more…)
Air Handler Water Coil Freeze Stat - The HVAC Air Handler Freeze Stat is a low-temperature limit control and it is used mainly in commercial systems in the duct work on economizers or in air handlers just before any coil especially water coils. It is a safety and protection control to prevent extremely cold air from reaching the hot water or chilled water coils inside the air handler where the air enters from the economizer. (more…)
Find Tonnage on AHU | HVAC Equipment Nomenclature - How do I find out the tonnage on a AHU? The label/tag has faded all I have on file is the model number and the serial number, make.
Question Posted By Francisco the Building Engineer on May 3, 2011
Refer to the manufacturers website for their HVAC nomenclature of the model number and serial numbers and how those numbers correspond to the tonnage and other technical data. Or you can call your local dealer for the manufacturer and they will tell you. (more…)
Refrigeration for HVAC
Air conditioners and heat pumps use the process of refrigeration to provide heating and cooling. What is the definition of the process of refrigeration? Refrigeration is the process of moving heat and depending on whether it is a heat pump or air conditioner and what mode it is in will depend where you are moving the heat. An air conditioner and a heat pump (in the cooling mode) will move heat outside. The evaporator coil absorbs the heat and the condenser rejects the heat. (more…)
About Chilled Water Systems | HVAC Hydronics
About Chilled Water Systems –
Chilled water systems are mainly used in large commercial HVAC air conditioning systems and industrial cooling applications although there are some residential and light commercial HVAC chilled water systems in use. Chilled water systems are popular because they use water as a refrigerant. Water is far less expensive than refrigerant. This makes them cost effective especially in commercial HVAC air conditioning applications. Instead of running refrigerant lines over a large area of the building water pipes are ran throughout the building and to evaporator coils in air handlers for HVAC air conditioning systems. The chilled water is pumped through these pipes from a chiller where the evaporator coil absorbs heat and returns it to the chiller to reject the heat.