definition of a HVAC zone - An HVAC zone can be defined as a cluster of adjacent offices and/ or spaces often covered by a common air-handling unit (AHU) or air terminal device.
list of analytical models assumptions.
- The air in the zone is fully mixed, and zone temperature distribution is uniform.
- The effect of North and South wall on the zone temperature is same. Also, the effect of East and West wall on the zone temperature is same.
- The ground/floor has no effect on the zone temperature.
- The density of the air is constant and is not influenced by changing the temperature and humidity ratio of the zone.
- No pressure losses across the zone and in the mixing section.
- Cz - Overall thermal capacitance of the zone - 47.1 kJ/C
- Tz - Zone Temperature - C
- Fsa - volume flow rate of supply fan - 0.192 m3/s
- ρa - density of air - 1.25 kg/m3
- Cpa - specific heat of supply air - 1.005 kJ/kgC
- Tsa - temperature of supply air - C
- Uw1 - overall heat transfer coefficient (East and west walls) - 2 w/m2C
- Uw2 - overall heat transfer coefficient (North and South walls) - 2 w/m2C
- Ur - overall heat transfer coefficient (roof) - 1 w/m2C
- Aw1 - Area (East and West walls) - m2
- Aw2 - Area (North and South walls) - m2
- Ar - Area (Roof) - m2
- Tw1 - temperature (East and West walls) - C
- Tw2 - temperature (North and South walls) - C
- Tr - temperature (Roof) - C
- q - heat gain for occupants and lights - W