I've used the following method in modeling indoor swimming pools/natatoriums
in eQuest:
For a Hotel Pool, ASHRAE guidelines call for pool water temperature to be
between 82-86F and the air temperature to be 82-85F (but also 2-deg F
greater than the pool water temp) and a RH range of 50-60%. I've used a
water temp of 82F and an air temp of 84F. I've also seen pool drawings with
a water temp of 80F in which I used an air temp of 82F. This design seems to
be more prevalent actually, so I'll use the 80F pool & 82F (50%RH) air.
The RATE OF EVAPORATION can be calculated by the following equation:
Wp = 0.1 x AREA OF POOL (sq ft) x (Pw - Pa) x Activity Factor (2007 ASHRAE
Handbook - HVAC Applications 4.6 Eq 2)
Wp is the evaporation of water lb/h
Pw is the saturation vapor pressure taken at surface water temp (in Hg)
Pa is the saturation pressure at room dew point (in Hg)
Activity Factor for a Hotel Pool is 0.8 (Residential pool is 0.5)
When you find your evaporation rate you can then multiply it by the Enthalpy
of saturated water vapor, or hg, which is in units of BTU/lb to find your
heat gain (BTU/hr).
In eQuest this heat gain can be added under the Building Shell for the Pool
space. In your Pool Space, under the Equipment tab, add an Internal Energy
Source. This is a Process source type and your Input Power is the calculated
heat gain (BTU/hr). I've been using a Latent HG ratio of 1.0.
Input this energy source and set the Heating/Cooling Thermostat control on
the space to 82/76 & Maximum Humidity control to 50 or 60%.
Verify your compressor load in the Detailed Simulation Output file.
I've used the following method in modeling indoor swimming pools/natatoriums
in eQuest:
For a Hotel Pool, ASHRAE guidelines call for pool water temperature to be
between 82-86F and the air temperature to be 82-85F (but also 2-deg F
greater than the pool water temp) and a RH range of 50-60%. I've used a
water temp of 82F and an air temp of 84F. I've also seen pool drawings with
a water temp of 80F in which I used an air temp of 82F. This design seems to
be more prevalent actually, so I'll use the 80F pool & 82F (50%RH) air.
The RATE OF EVAPORATION can be calculated by the following equation:
Wp = 0.1 x AREA OF POOL (sq ft) x (Pw - Pa) x Activity Factor (2007 ASHRAE
Handbook - HVAC Applications 4.6 Eq 2)
Wp is the evaporation of water lb/h
Pw is the saturation vapor pressure taken at surface water temp (in Hg)
Pa is the saturation pressure at room dew point (in Hg)
Activity Factor for a Hotel Pool is 0.8 (Residential pool is 0.5)
When you find your evaporation rate you can then multiply it by the Enthalpy
of saturated water vapor, or hg, which is in units of BTU/lb to find your
heat gain (BTU/hr).
In eQuest this heat gain can be added under the Building Shell for the Pool
space. In your Pool Space, under the Equipment tab, add an Internal Energy
Source. This is a Process source type and your Input Power is the calculated
heat gain (BTU/hr). I've been using a Latent HG ratio of 1.0.
Input this energy source and set the Heating/Cooling Thermostat control on
the space to 82/76 & Maximum Humidity control to 50 or 60%.
Verify your compressor load in the Detailed Simulation Output file.
Michael M. Collarin, EIT