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Radial fan
A radial fan is a device that consists of an impeller driven by an electrical motor. The rotation of the impeller sets the air in motion and air is sucked in from the inlet on the side of the fan and blown out of the outlet of the fan.
Radiator exponent
The radiator exponent n indicates the change in heat output of a radiator when the actual conditions, in terms of water temperature and room temperature, differ from standard conditions, i.e., the values that were used to define a radiator’s nominal heating capacity.
Radiant heating
Radiant heat is thermal radiation between two surfaces. Thermal radiation occurs when a material transmits infrared radiation, thereby warming a second material, without causing the air around the materials to be heated.
Radiator
A radiator is a heating surface that transfers a significant part of its heat by thermal radiation and the rest by convection.
Recirculation pump
The function of the recirculation pump is to ensure that hot water is always available as close to the consumption point as possible, in order to reduce water wastage and to increase comfort.
Reciprocating compressor
Reciprocating compressors are often used in connection with cooling systems. A reciprocating compressor draws in coolant fumes in portions, while other compressor types draw continually.
Refrigerant charge
Refrigerant charge is a term used for the type and mass of refrigerant a refrigeration plant will hold to perform under the given conditions. The type of refrigerant must be applicable for the application and the ambient conditions. For example, the ASHRAE standards are general recommendations regarding local ambient conditions for inside and outside temperatures in both summer and winter in any country.
Recycling
Recycling is the creation of new products from used materials. Recycling is not the same as reuse, where the object is reused for its original purpose.
Relative humidity
Relative air humidity is a term used to describe the amount of water vapour in the air. Relative air humidity is the ratio of the water vapour’s partial pressure to the saturated vapour pressure at a given temperature. Relative air humidity is expressed as a percentage.
Refrigerant
The task of the refrigerant is to transfer energy from one level and dispose of it at a higher level. There are many different types of primary refrigerants, each with technical substance characteristics, such as pressure, temperature, heat content, specific volume, and entropy for every need.