How to choose swimming pool heat pump ?
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- Mar 14,2017
How to choose swimming pool heat pump ?
When pool water in a low temperature in Winter, it can use swimming poolheat pump to get warm water and can keep it in 28-31℃, thus it can swimming allyear. The design of swimming pool waterconstant temperature project, it needs to calculate how much heat for initialheating and constant temperature heating. It needs to calculate heat radiation and choose the suitable heating capacityswimming pool heat unit.
For example: If indoor swimming pool length 12m, width 4m, and depth 1.5m. The volume is 72 m³. The area indoor dry bulb temperature is 7℃ (averagetemperature of the coldest month ), tap water temperature is 8℃ (average water temperature of the coldest month), and the swimmingpool constant temperature setting is 28±1℃,water specific heat is 1kcal/kg·℃. And if the swimming poolwater target temperature setting is 28℃, indoor average ambient temperature is 20℃,relative humidity is 70%.
Initial heating (without heat radiation)
Ifinitial heating time is 48h, then:ature heating. It needs to calculate heat radiation and choose the suitable heating capacityswimming pool heat unit:
Q1: heating capacity of swimming pool(kcal/h)
Qrd: volume of swimming pool 72000L
C:water specific heat, c=1kcal/(kg)
Pr: water density,1kg/L
Tr: stop running setting water temperature of storage tank, 28℃
Tl: Tap water temperature,8℃
T: heating time,48h
Q1=72000L×(28℃-8℃)/48h=30000kcal/h
The heat load of constanttemperature of swimming pool include: heat loss of pool water evaporation, heattransfer loss of pool surface, bottom, side, pipes and equipments, and heatloss of compensation fresh water.
1.Heat loss of pool water evaporation:
Qz: Heat loss of pool water evaporation(kcal/h)
β:water pressure conversion coefficient 133.32Pa
ρ: water density 1.0kg/L
у: pool water equal temperature evaporating latent heat of vaporization584kcal/kg
VW :wind speed of swimming pool upside (m/s),normal indoor pool VW =0.2~0.5 m/s and outdoor VW =2~3m/s
Pb: water vapor pressure of relative pool water temperature 28℃ saturated air 3780Pa
Pq: water humidity 70%,indoor temperature 7℃ steam pressure 620Pa
A:pool water surface square
B: normal atmospheric pressure 760Pa
B’: local atmospheric pressure760Pa
Qz =(1/133.32Pa)×1.0kg/L×584kcal/kg×(0.0174×0.5m/s+0.0229)×(3780Pa-620Pa)×48m2×(760Pa/760Pa)=20993kcal/h
2. Heat transfer loss of poolsurface, bottom, side, pipes and equipments, it need calculate as 20% heat lossof pool water evaporation:
Qs=20%×Qz=20993kcal/h×20%=4198kcal/h
3. Pool compensation fresh water heat loss:
Qb: heating capacity of fresh water(kcal/h)
qb: every day need fresh water’s volume(L),72000L×5%
у: water density 1.0kg/L
tr: pool water target temperature 28℃
tb: fresh water temperature 8℃
T: heating time 24h
Qb=72000L×5%×1.0kg/L×(28℃-8℃)/24=3000kcal/h
Swimming pool initial heating capacity:
Q1+(Qz+Qs)/2=30000kcal/h+(20993kcal/h+4198kcal/h)÷2=42596kcal/h
Swimming pool constant temperature heatingcapacity:
Qz+Qs+Qb=20993kcal/h+4198kcal/h+3000kcal/h=28191kcal/h
Swimming pool heat pump unit select modeland quantity:
If 6HP heat pump unit output15000kcal/h inoutdoor ambient temperature 7℃
①swimming pool constant installed unitcapacity:28191kcal/h÷15000kcal/h.unit=1.87unit
②swimming pool initial heating installedunit capacity:42596kcal/h÷15000kcal/h.unit=2.84unit
③Thus this project need 3units of 6HP heatpump units.
To know more information, please do not hesitate to contact Real Power team sales@realpowertech.com