Superheating with Pressure Transducers in Refrigerant Cycle
Controlling the Superheat
Medical equipment often needs internal cooling systems. MRI machines, X-ray machines, and home health air supplies all require some combination of air conditioning, refrigeration, and humidification or dehumidification. Typical compressor-driven air conditioning units used for medical equipment cooling make use of the refrigerant cycle. The refrigeration cycle consists of an evaporator, a compressor, a condenser, an expansion valve, and system monitoring devices like temperature and pressure transducers.
The refrigerant cycle consists of the following process: A cool, low-pressure gaseous refrigerant enters the compressor. Next, a hot, high-pressure gaseous refrigerant leaves the compressor, enters the condenser, and releases heat to the outside environment. At this point, hot, high-pressure liquid refrigerant leaves the condenser coil and enters the expansion valve, which reduces both the pressure and temperature of the liquid refrigerant. A cold, low-pressure liquid refrigerant absorbs heat from inside to cool the environment and then leaves the evaporator as a cool, low-pressure gas. The cycle repeats itself.
As efficiency and energy conservation gain importance in today’s society, controlling the superheat of refrigeration cycles has emerged as a simple method to greatly increase the efficiency of air conditioning units. Superheat in the HVAC industry is defined as the difference in temperature between the boiling temperature of the refrigerant and the actual temperature of the refrigerant as it leaves the evaporator coil.
The goal to controlling the superheat is to minimize it. This can be done through pressure measurement and temperature measurement using electronic temperature and pressure transducers at the evaporator coil outlet and the compressor inlet.
Pressure measurement and temperature measurement give specific insight into how to modify the flow rate of refrigerant used to maximize the efficiency of the air conditioning unit. When faster cooling is required, automated processes can increase refrigerant flow rate. As less cooling is required, automated processes can decrease the refrigerant flow rate. The automated processes are dependent on accurate, dependable temperature and pressure transducers.
Pressure Transducer Application for Controlling the Superheat in Medical Equipment Applications
Pressure transducers are used for controlling the superheat in HVAC and refrigeration in the following medical equipment applications:
- Compressor Inlet Pressure
- Compressor Inlet Temperature (with WIKA Electronic Temperature products)
- Evaporator Coil Outlet Pressure
- Evaporator Coil Outlet Temperature (with WIKA Electronic Temperature products)
- Expansion Valve Flow Rate Monitoring
Controlling the superheat in medical equipment applications calls for pressure transducer material compatibility with refrigerants, wide pressure ranges, sanitary instrumentation, and medical grade gases. Pressure transducers are responsible for providing pressure measurement information about the evaporator outlet and the compressor inlet to minimize air conditioning superheat and maximize air conditioner efficiency, as well as monitor and regulate the flow rate of refrigerant through the expansion valve. The WIKA Refrigeration and Air Conditioning Pressure Transmitters types R-1 and AC-1 have been designed for performance, reliability, and compatibility with internal cooling systems for medical equipment.