Heating Load Calculation in Swimming Pool

Heated swimming pool heating under the name of the swimming pool, hot water supply, heat exchanger and the necessary resources research for the heating load calculation to be used in the selection and design of installations yapılmıştır.hesap results differ greatly depending on usage and environmental conditions, the pool is the necessary heat accounts for depicts heating also yapılmaktadır.kullanıc with the preferences and aspirations sample results at the end etkilemektedir.çalış to account for the differences will be discussed.

Heating the pool water is done for two purposes;

  1. Increasing the comfort requirements
  2. Extending the lifetime of the pool

So just to ensure all-year use of the pool available in the summer season and is already possible with minimized to only the right design in the investment and operating costs bulunmaktadır.Bu cost of heating the economic return arttırılmaktadır.ancak pool water operation of the pool, which made investments constructive.

Heat Loss for Heating and Gain Account in Swimming Pool

The following table lists the recommended temperature for the swimming pool water.

Table 1: The recommended temperature of the pool water use for different purposes [1]

Public pools 26-28
Sports pools 22-24
Children’s pools 26-32
Therapy pools 35
Massage pools 32-26
Cold water (shock) pools 15

Heat Loss Calculations

Convection heat loss from the water surface with (Q t kcal / m²h)

heat loss in outdoor pools is calculated by the following formula.

Q t = α t * (t -t h C) [2] (1)
t h = pool water temperature (° C)
t d = Ambient air temperature (° C)
α t = water surface convection coefficient (kcal / m²hºc).
t = 1.8 * α ν + 1.65 [2] (2)
ν = air velocity at the surface of the water (m / s)

Table 2: water surface for outdoor pools depending on the air velocity values of α t

Outdoor pool protected Outdoor swimming pool semi-protected Outdoor pool unprotected
ν one 2nd 4
α t 3.5 6.0 11.0

In the indoor swimming pool, room temperature is usually done by heating with convection heat loss comes from the pool water temperature is kept high in the indoor pool environment değildir.ancak Qt= 10 kcal / m²h be. [3]

Radiative heat loss from the water surface with (Q i, kcal / m²h)

heat loss in outdoor pools is calculated by the following formula.

Q i = R * θ * (t -t h d) [3] (3)
Contact coefficient R = (applying 5 kcal / m²hºc 4)
θ = temperature factor (in practice 1 ° C)
t h = pool water temperature (° C)
t d = Ambient air temperature (° C)

In indoor swimming pool heat loss by radiation, in the living room wall again and again.The water account due to the reflection from the roof will not be considered. [3]

Evaporation from Water Surface with Heat Loss (Q b kcal / m²h)

Heat loss is calculated by the following formula.

Q b = σ * (m -m NH DH) * h s [4] (4)
Do you have dH = the amount of water in the saturated air at the water surface (kg / kg of dry air)
m nh = ambient temperature and the amount of water in the air having a relative humidity (kg / kg dry air)
h r = heat of vaporization of water in the pool water temperature (in practice 580 kcal / kg)
σ = coefficient of evaporation (Lewis number, kg / m²h)
σ = 25 + 19 * ν [4] (5)

Table 3: σ value according to the pool type

Indoor pool Outdoor pool protected Outdoor swimming pool semi-protected Unprotected outdoor pool
ν 0.6 one 2nd 4
σ 36 44 63 101

Feed Water Temperature Requirements (Q e kcal / m²h)

Evaporation by heating the water to the pool water temperature added to complete the heat required for diminishing the pool of gerekir.b calculated using the following formula.

Q e = σ * (m dh -m NH) p * C * (t v -t b) [4] (6)
σ = coefficient of evaporation (can be taken from Table 3)
Do you have dH = the amount of water in the saturated air at the water surface (kg / kg of dry air)
m nh = ambient temperature and the amount of water in the air having a relative humidity (kg / kg dry air)
C p = specific heat of water (C p = 1 kcal Water / kgºc)
t h = pool water temperature (° C)
t b = Supply water temperature (° C)

And Refreshing Splash Water Heat Requirement (Q s, kcal / m²h)

In addition to the evaporation of water in swimming pools, splash and wash the filter unit, etc. events occur and additional water loss.

According to experience in this way the amount of water loss 0.6 kg / m²h be [3] According to the heat requirement of approximately .B;

Q s = 10 kcal / m²h acceptable. [3]

Heat Gain Account

Solar Radiation and Heat Gain (Q g Kcal / m²h)

The amount of solar radiation from the Earth’s surface

* The facility to the location (latitude)

* Changing daily solar radiation throughout the year

* Sun duration (length of day, cloud cover)

It depends on such variables.

The outdoor swimming pool Q g = 150 kcal / can be used as m²h. [5]

In the indoor pool it is not mentioned radiation gain.

I moved from the water surface with Heat Gain (Q k Kcal / m²h)

heating required during periods of ambient temperature due to convection heat gain oluşmaz.b with midwives from the pool water temperature in the outdoor pool, also applies to medium heat made indoor swimming pools.

In space heating is carried out according to the ambient temperature indoor swimming pool, it should be more than the pool water temperature 2-3ºC Q k = 20 kcal / m²h get enough.

Total Heat Gain – Loss

Examples of conditions that made for the Aegean coast below pool heating requirement calculation results verilmiştir.b values are for information only, project objectives and work done by the special environmental conditions kullanılamaz.hesap with each pool must be designed.

Table 4: A general statement of the need for heating pools in the Aegean coastal region

Indoor swimming pool (heated) Indoor pool (unheated) Outdoor swimming pool (protected) Outdoor swimming pool (semi-protected) Outdoor swimming pool (unprotected)
Heat loss
Convection Qt 10 63 108 198
Radiation Q i 90 90 90
Evaporation Q b 200 240 290 420 670
Feed Q e 7 7 10 13 21
Splash-refresh Q s 10 10 10 10 10
The total heat loss 217 267 463 641 989
Heat gain
Radiation Q g 150 150 150
Convection Q k 20 0 0 0
total heat gains 20 150 150 150
The total heat requirement Qoutput 197 267 313 491 839

The following assumptions were used in preparing the above table.

Pool water temperature 28 ° C
40% relative humidity ambient air conditions 10ºC-
The air temperature at 20 ° C Water surface
Supply temperature of 10ºC

First Heating Heat Requirement Calculation (Qd, Kcal / H)

The amount of heat required for the initial heating of the pool water is calculated by the following formula.

Q d = m + 1000 * V * A * Q * C p (t v -t b) / h (7)

A = Pool surface area (sqm)
Q m = Wall heat loss (20 kcal / m²h be) [3]
V = pool water volume (m³)
C p = specific heat of water (C p = 1 kcal Water / kgºc)
t h = pool water temperature (° C)
t b = Supply water temperature (10 ° C may be)
h d = First heating (h)

First heating time alınabilir.sür the shorter the heating system between 24-72 hours depending on operating conditions and should not be overlooked supplies will grow.

Example Heat Requirement Calculation and Selection of Heat Exchangers

Accounts will be made to pool the features below.

Pool type Open-unprotected
Pool surface area 200 m²
Pool water volume 330 m³
Water temperature 28ºC
Feed water temperature 10ºC
First heating time 48 h
Safety factor 13%
Thermal energy supply Boiler (75 / 55ºC)

Thermal Requirements

a) normal operating temperature requirement (Qn, kcal / h)

Q c = 839 kcal / m²h (Table 4)
Q * = 1.13 * 200 m² 839 kcal / m²h
Q n = 189,614 kcal / h
b) The initial heating temperature requirement (Qd, kcal / h)

In the first warm-up account is not required to use a safety factor.

Q d = 200 m² * 20 kcal / m³ m²h + 1000 * 330 * 1 kcal / kgºc * (28ºC-10ºC) / 48
Q d = 113 830 kcal / h

Since the heat requirement is greater than the first heating occurs during normal operation of the heating system in the design Q = 189,614 kcal / h is used.

Heat Exchanger Selection

Plate Heat Exchangers to heat the pool water in the system will be used.

Exchanger type and size of the installation to be selected to form a connection to the exchanger and a need for business information below.

Fluid Primary Boiler Water Secondary Pool Water units
Capacity 189614 kcal / h
Inlet Temperature 75 25 ºC
Outlet temperature 55 50 ºC
The pressure drop (*) 2nd 2nd mss

(*) Maximum pressure drop permitted transducers formed on both sides will depend on the pump.

Plate Heat Exchanger Technical Data Sheet and Dimensioning

Thermal data hot Party cold Side
Heat capacity: 189614 kcal / h
Flow rate: 9.6 7.6 m³ / h
Inlet temperature: 75.00 25.00 ° C
Outlet temperature: 55.00 50.00 ° C
Pressure drop 1:32 0.78 mss
Logarithmic temperature difference: 27.42 K
Converters information
The overall heat transfer area: 2:30
Total plate count: 22
Plate thickness 0.00060 m
Surface excess rate: 7.95 %
Plate material: 1.4401
Sealing material: NBR
Design temperature: 140.00 ° C

Pool Water Heating System for Sample Account System Plan [7]

Plumbing pipe diameters; Ød 5 = 2 “… ..Ød 6 = 2″ … ..Ød 7 = 2 ½ ”

A list of materials;

7 Manometer Ø100 5 Bar
8 Spherical ½ “
12 Spherical 2nd”
13 strainer 2nd”
14 Reduction 2 “> 1½”
15 Circulation pump 8.8 m³ / h; 6 mss
16 Thermometer Ø100 0-120 ° C
17 Spherical ½ “
18 Flow switch (flow switch)
19 Temperature sensor
20 Plate heat exchanger VT10 / 22 plan 188,830 kcal / h
21 Reduction
22 Reduction 2 ½ “> 2”
23 Thermometer 0-120 ° C
24 Spherical 2 ½ “
25 strainer 2 ½ “
26 Reduction 2 ½ “> 2”
27 Circulation pump 11 m³ / h; 6 mss
28 Pump control panel 19≥T stop 27 or 18 ⇓ ⊃


Pool heat losses, depending on the type and design requirements necessary as a result of differences gösterebilmektedir.b close to four times the heating system as well as investment in heating operating costs vary.

Pool plumbing design of the operator to be informed about it before and making more investment economic measures to be taken with the aim olacaktır.b possible;
1-First heating time should be kept as long as conditions allow, and should be identified as realistic.
Outdoor pool 2-velocity air in the pool surface in order to minimize environment windbreak should be applied.
3-in time is not used in the first heating and pool in the outdoor pool, especially at night, the water surface should be covered with plastic sheeting.
4-insulation should be done in all heating systems.

You can download the excel program related to heating the swimming pool account on the above information.

Heating Load Calculation Program in Swimming Pool
Explanation Download Link
pool-heat-loss-account Excel pool-heat-loss-hesabi.xls
practice-pool-heating-account Excel practice-pool-heating-hesabi.xls
pool-water-exchanger-secimi Excel pool-water-exchanger-secimi.xls
pool-water-heating-account Excel pool-water-heating-hesabi.xls

Source: Cuneyt ÖZYAMAN, Mechanical Engineer, DOPA Ltd. Ltd.

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