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[15] [16] For example, to maintain a 15 °C temperature in a certain dwelling about 3.0 kW of heating are required at 0 ACH (no heat loss due to warmed air leaving the dwelling, instead heat is lost due to conduction or radiation), 3.8 kW at 1 ACH and 4.5 kW are required at 2 ACH. [15] The use of roof space for heating or cooling was seen as ...
The CLTD/CLF/SCL (cooling load temperature difference/cooling load factor/solar cooling load factor) cooling load calculation method was first introduced in the 1979 ASHRAE Cooling and Heating Load Manual (GRP-158) [1] The CLTD/CLF/SCL Method is regarded as a reasonably accurate approximation of the total heat gains through a building envelope ...
In cold climates, with a 15 MPH wind, residences often have air exchange rates of 1.0 to 1.5 ACHs, far in excess of the ventilation air needs and are thus called loose construction. It is very easy to reduce infiltration rates to less than 1.0 ACH. Smoke candles and blower-door tests can help identify less-than-obvious leaks.
Displacement ventilation systems supply air directly to the occupied zone.The air is supplied at low velocities to cause minimal induction and mixing. This system is used for ventilation and cooling of large high spaces, such as auditorium and atria, where energy may be saved if only the occupied zone is treated rather than trying to control the conditions in the entire space.
Conventional overhead mixing systems usually locate both the supply and return air ducts at the ceiling level. Supply air is supplied at velocities higher than typically acceptable for human comfort and the air temperature may be lower, higher, or the same as desired room temperature depending on the cooling/heating load.
The building balance point temperature is the outdoor air temperature when the heat gains of the building are equal to the heat losses. [1] Internal heat sources due to electric lighting, mechanical equipment, body heat, and solar radiation may offset the need for additional heating although the outdoor temperature may be below the thermostat set-point temperature.
The ASHRAE Handbook is the four-volume flagship publication of the nonprofit technical organization ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers [a]). This Handbook is considered the most comprehensive and authoritative repository of practical knowledge on the various topics that form the field of heating ...
Constant air volume (CAV) is a type of heating, ventilating, and air-conditioning system. In a simple CAV system, the supply air flow rate is constant, but the supply air temperature is varied to meet the thermal loads of a space. [1] Most CAV systems are small, and serve a single thermal zone.