fluid discharge temperature, and COP (the ratio between the cooling capacity in RT to the energy consumed by the whole chiller in kW). For medium to large chillers this should range from 3.5 to 7.0, with higher values meaning higher efficiency. In the US, chiller efficiency is often specified in kilowatts per refrigeration ton (kW/RT). Process pump specifications that are important to consider include the process flow, process pressure, pump material, elastomer and mechanical shaft seal material, motor voltage, motor electrical class, motor IP rating and pump rating. If the cold water temperature is lower than −5 °C, then a special pump needs to be used to be able to pump the high concentrations of ethylene glycol. Other important specifications include the internal water tank size and materials and full load current. Control panel features that should be considered when selecting between industrial chillers include the local control panel, remote control panel, fault indicators, temperature indicators, and pressure indicators. Additional features include emergency alarms, hot gas bypass, city water switchover, and casters. Demountable chillers are also an option for deployment in remote areas and where the conditions may be hot and dusty. If noise levels of the chiller are acoustically unacceptable, noise control engineers will implement sound attenuators to reduce chiller noise levels. Larger chillers will typically require an array of sound attenuators sometimes known as a silencer bank. Refrigerants A vapor-compression chiller uses a refrigerant internally as its working fluid. Many refrigerants options are available; when selecting a chiller, the application cooling temperature requirements and refrigerant's cooling characteristics need to be matched. Important parameters to consider are the operating temperatures and pressures. There are several environmental factors that concern refrigerants, and also affect the future availability for chiller applications. This is a key consideration in intermittent applications where a large chiller may last for 25 years or more. Ozone depletion potential (ODP) and global warming potential (GWP) of the refrigerant need to be considered. ODP and GWP data for some of the more common vapor-compression refrigerants (noting that many of these refrigerants are highly flammable and/or toxic): R12 is the ODP reference. CO2 is the GWP reference The refrigerants used in the chillers sold in Europe are mainly R410a (70%), R407c (20%) and R134a (10%). See also Tube tool Architectural engineering BTU Building services engineering Chemical engineering Cooling tower Evaporative cooling Free cooling Heat Pump HVAC Mechanical engineering MOKON