The daily hot water consumption of the installation is calculated according to the following dependence:
| \[m_{DHW} = person_{n}\cdot person_{DHW}\] | (1) |
|---|
Where:
`person_{n}` - number of people using DHW;
`person_{DHW}`- daily consumption of hot water by one person, [l/d];
For this purpose, the surface of the DHW boiler is calculated as follows:
| \[A_{tank}=π\cdot D_{tank}\cdot L_{tank}+2\cdot π \cdot \frac{D_{tank}^{2}}{4} ,[m^{2}]\] | (2) |
|---|
Where:
`D_{tank}` - the diameter of the hot water boiler, [m];
`L_{tank}` - the length (height) of the DHW boiler, [m];
The DHW load per month is calculated according to the following dependence, taking into account the heat losses from the boiler:
| \[Load_{DHW,i} = \frac{m_{DHW}}{1000}\cdot p_{w}\cdot cp_{w}\cdot\left(t_{DHW}-t_{c,w,i}\right)\cdot Days_{i}\cdot |2,77778\cdot10^{7}\frac{MWh}{kJ}|+U_{tank}\cdot A_{tank}\cdot \left(t_{DHW}-T_{room}\right)\cdot Days_{i}\cdot |0,001\cdot\frac{MWh}{kWh}|\] | (3) |
|---|
Where:
`cp_{w}` - the specific heat capacity of the water set at the desired DHW temperature and at the working pressure of the water mains, [kJ/kgK];
`r ho_{w}`- the water density determined at the desired DHW temperature and the working pressure of the water mains, [kg/m3];
`t_{DHW}` - the desired DHW temperature, [°C];
`t_{c,w,i}` - the temperature of the cold water entering from the water main for the respective month, [°C];
`Days_{i}` - the number of days for that month;
`U_{tank}` - the heat transfer coefficient of the DHW cylinder, [W/m2K];
`T_{room}` - the air temperature in the room where the DHW cylinder is installed, [°C];
Dependency (3) is calculated 12 times for each month i=1..12.
The proportion of energy required to heat the water covered by the solar thermal installation is calculated using the F method.
For this purpose, the dimensionless parameters X and Y are calculated from the following dependencies:
| \[X=F_{R} U_{L}(F'_{R}/F_{R})(θ_{ref}-θ_{e}) Δτ\frac{A_{c}}{Q_{w}}\] | (4) |
|---|
| \[Y=F_{R}(τα)_{n}(F'_{R}/F_{R})[(\overline{τα})/(τα)_{n}] \overline{H}_{T} N \frac{A_{c}}{Q_{w}}\] | (5) |
|---|
Where:
`A` - is the area of solar collectors in the solar thermal installation, [m2];
`F_{r}` - the coefficient of effective heat removal from the collector, also taking into account the influence of the intermediate heat exchanger in the collector circuit;
`U_{l}` - the total heat loss coefficient of the collector, [W/m2K];
`Δ\tau` - the number of seconds in the corresponding month;
`\theta_{ref}=100°C` - the basic temperature;
`\theta_{e}` - the average monthly outside air temperature for that month, [°С];
`(τα)` - the average monthly absorption capacity of the collectors;
`(τα)_{n}` - the average monthly absorption capacity of the collectors at perpendicular radiation on their surface;
`H_{T}` - the average monthly total solar radiation on the inclined surface of the collectors, [J/m2];
`N` - the number of days in the month, e.g. `Days_{i}`;
`Q_{w}` - the monthly heat load of the system determined by dependency (3) for the corresponding month, [J];
The solar part of the solar thermal installation is defined by the following dependence:
| \[f=1,029\cdot Y-0,065\cdot X-0,245\cdot Y^{2}+0,0018\cdot X^{2}-0,0215\cdot Y^{3}\] | (6) |
|---|
Having the following limitations 0 < Y < 3 и 0 < Х < 18
If the dimensionless parameters X and Y are larger than the above-mentioned limits, then the dependency of the parameter `f` on dependency (6) is assigned a value of 1, i.e. the solar installation share is 100%.
Dependency (6) is valid for installations with a specific accumulation volume of 75 [l/(m2] collector area.
In case the specific accumulation volume of the solar thermal installation is different from 75 [l/m2], the dimensionless complex X is corrected according to the following dependence:
| \[\frac{X_{c}}{X}=\left(\frac{V_{c}}{75A_{c}}\right)^{-0,25} \rightarrow 37,5 < \frac{V_{s}}{A_{c}} < 300,[l/m^{2}]\] | (7) |
|---|
Where `V_{s}` is the volume of the acumulator / DHW boiler /, [m3].
Depending on the configuration of the solar thermal installation, it may be of a direct type (without intermediate heat exchanger) or indirect type (with an intermediate heat exchanger).
For this purpose a correction of the coefficient of effective heat removal from the collector is used, which takes into account the influence of the intermediate heat exchanger, its efficiency and the type of the used coolant in the collector circuit and in the installation.
| \[F'_{R}/F_{R}=1\] | (8) |
|---|
When there is no heat exchange apparatus in the system, the correction of the effective heat output coefficient from the collector is as follows:
| \[\frac{F'_{R}}{F_{R}}=\left[1+\left(\frac{A_{c} F_{R} U_{L}}{\left(ṁ c_{p}\right)_{c}}\right) \left(\frac{\left(ṁ c_{p}\right)_{c}}{ε\left(ṁ c_{p}\right)_{min}}-1\right)\right]\] | (9) |
|---|
Where:
`(ṁc_{p})_{c}` - the heat capacity of the mass flow of the fluid through the contour of the solar collectors, [W/K];
`\epsilon` - efficiency of the intermediate heat exchanger;
`(ṁc_{p})_{min}` - the lower heat capacity of the mass flow of the fluids circulating through the heat exchanger, [W/K];
Finding the solar fraction from the solar thermal installation for the respective month is done by applying dependencies from (4) to (9) incl. for each month.
The energy obtained from the solar thermal installation for the respective month is calculated according to the following dependency:
| \[Q_{solar,i}=f_{i}\cdot Load_{i}, [kWh]\] | (10) |
|---|
Където:
`f_{i}` - the solar share for that month;
`Load_{i}` - the DHW load for that month;
The required DHW energy per year is calculated by the following dependency (as a sum of the individual loads by months /:
| \[Load=\sum_{i=1}^{12} [Load_i], [kWh]\] | (11) |
|---|
The solar share of the solar thermal installation on an annual basis is calculated according to the following dependency:
| \[F= \frac{\sum_{i=1}^{12} [f_iLoad_i]}{Load} \] | (12) |
|---|
For this purpose, it is necessary to use climatic data for the daily amount of solar radiation on a horizontal surface for the respective location. This data can be obtained from the embedded database, or the user inserts them on their own. Average monthly solar radiation on an inclined surface is determined by the following dependency:
| \[\overline{H}_{T}=\overline{R}\cdot\overline{H}\left[kWh/m^{2} ден\right]\] | (13) |
|---|
Where:
`\overline{R}` - the correction factor, which is a ratio of full solar radiation of a randomly oriented inclined surface to full solar radiation on a horizontal surface;
`\overline{H}` - average daily solar radiation on a horizontal surface, [kWh/m2 ден];
The correction factor R can be calculated using the following dependency:
| \[\overline{R}=\left(1-\frac{\overline{H}_{d}}{\overline{H}}\right)\cdot\overline{R}_{b}+\frac{\overline{H}_{d}}{\overline{H}}\cdot\left(\frac{1+\cos\beta}{2}\right)+\rho\cdot\left(\frac{1-\cos\beta}{2}\right)\] | (14) |
|---|
Where:
`\overline{R_{b}}` - the ratio of the average monthly direct sun radiation to the inclined and the horizontal surface;
`\overline{H_{d}}` - average daily diffuse radiation over a horizontal surface, [kWh/m ден];
`\beta` - angle of inclination of the surface under consideration / angle of inclination of the solar collectors to the horizon/, [o] ;
`\rho` - the reflection coefficient of the solar radiation from the environment (in particular from the earth's surface). In the absence of data, an average annual value of 0.4 may be taken, or individual values for each month, reflecting the presence of snow cover, vegetation type, etc. may be used.;
The ratio `\frac{\overline{H}_{d}}{\overline{H}}` is determined by the following dependency:
| \[\frac{\overline{H}_{d}}{\overline{H}}=1,39-4.03\cdot\overline{K}_{T}+5,53\cdot\overline{K}_T^2-3.11\cdot\overline{K}_T^3\] | (15) |
|---|
Where `\overline{K_{T}}` is the cloud factor.
The cloud factor can be calculated as the ratio of the average daily solar radiation on a horizontal surface to the average daily solar radiation behind the atmosphere.
| \[{H}_{d}=\frac{86400\cdot I_{SC}}{\pi}\cdot\left(1 + 0,033\cdot\cos\left(2\pi\frac{n}{365}\right)\right)\cdot\left(\cos\phi\cdot\cos\delta\cdot\sin\omega_{s} + \omega_{s}\cdot\sin\phi\cdot\sin\delta\right)\] | (16) |
|---|
Where:
`\delta` - the declination of the sun / determined for the respective day of the monthi/, [o];
`\omega_s^\prime` - hour sunset angle on a horizontal surface / determined for the respective day of the month dayi/, [o];
`\omega_s` - hour sunset angle on the inclined surface / set for the respective day of the month dayi/, [o];
`\phi` - latitude, [o].
`I_{sc}` = 1367 [W/m2] is the solar constant;
`n` – the number of the day from the beginning of the year / 01.01 is day number 1 of the year, 31.12. is the day number 365 from the beginning of the year /; The variable `day_{i}` can be assumed to be a constant (21st day of month). In the specific case, to improve the accuracy of the model, we work with different values for each month presented in the following array:
| \[day_{i}=[17,16,16,15,15,11,17,16,15,15,14,10]\] | (17) |
|---|
The hour angle of sunset on a horizontal surface is determined by the following dependency:
| \[\omega_{s}=\arccos\left(-tg\phi\cdot tg\delta\right)\] | (18) |
|---|
The hour angle of sunset on the inclined surface is determined by the following dependency:
| \[\omega_{s}^\prime=min\left[\omega_{s};\arccos\left(-tg\left(\phi-\beta\right)\cdot tg\delta\right)\right]\] | (19) |
|---|
The declination of the sun for the respective month is calculated by the following dependency:
| \[\delta=23,45\cdot\frac{\pi}{180}\cdot sin\left[2\pi\cdot\left(\frac{284 + n}{36,25}\right)\right] \] | (20) |
|---|
The ratio of the average monthly solar radiation on the slope and the horizontal surface is calculated by the following dependencъ:
| \[\overline{R}_{b}=\frac{\cos\left(\phi-\beta\right)\cdot\cos\delta\cdot\sin\omega_{s}+ \pi/180\cdot\omega\prime_{s}\cdot\sin\left(\phi-\beta\right)\cdot\sin\delta}{\cos\phi\cdot\cos\delta\cdot\sin\omega_{s}+ \pi/180\cdot\omega\prime_{s}\cdot\sin\phi\cdot\sin\delta}\] | (21) |
|---|
Calculation of the heating load of a building is done in a simplified methodology, including a load of heat transfer, ventilation and infiltration.
The load of heat transfer is calculated through the enclosing elements (floor, ceiling, walls, windows and doors). For this purpose, it is necessary for the user to enter the corresponding values of the heat transfer coefficients of the respective type of enclosing element. If the building is a new building, then the user does not need to enter values of the heat transfer coefficient, and for this purpose the normative values are used.
In this case, it is assumed that the building has a "standard form" representing a parallelepiped or a cube If the building is of a complex or irregular shape, the user should first calculate the areas of the individual enclosures and introduce new dimensions / length, width and height), so that with the new dimensions the same areas of the enclosing elements as those of the actual building are obtained.
The heat transfer load for the entire building is calculated according to the following dependency:
| `Q_{T}=\sum_(i=1)^nU_{i}\cdotA_{i}\cdot(\theta_{i}-\theta_{\alpha}),[W]` | (1) |
|---|
Където:
`Q_{T}` - is the heat load for the entire building [W];
`i` - the type of enclosure / floor, ceiling, exterior walls, windows and doors /;
`U_{i}` - the heat transfer coefficient of the respective enclosing member, [W/m2];
`A_{i}` - the area of the surrounding enclosure, [m2];
`\theta_{i}` - the calculated average indoor air temperature inside the building, [oC];
`\theta_{\alpha}` - the calculated average outside air temperature for that month, [oC];
Dependency (1) shall be applied 12 times for each month of the year.
In case the average daily outside air temperature is higher than the reference temperature `\theta_{b} = +13^0C`, then it is assumed that the building does not need heating and the heating load is zero.
The heating load from infiltration is calculated by the following dependency:
| \[Q_{инф.} = 0,24.V.(\theta_i - \theta_\alpha), [W]\] | (2) |
|---|
Където `V` - is the net volume of the entire building [m3];
The heating load from ventilation is calculated according to the following dependency:
| \[Q_{вент.} = 0,33.n.V.(\theta_i - \theta_\alpha), [W]\] | (3) |
|---|
Where `n` - is the average multiplicity of air exchange for the entire building, [h-1];
The calculative heating load of the building for the respective month is calculated according to the following dependency:
| \[Q_{H}=Q_{T}+\max(Q_{вент.};Q_{инф.}), [W]\] | (4) |
|---|
Dependencies from (1) to (4) incl. are calculated 12 times for each month.
The total heating load of the building per year is calculated according to the following dependency:
| `Q_{H,\alpha}=\sum_(i=1)^12[Q_{T}+\max(Q_{вент.};Q_{инф.})],[W]` | (5) |
|---|
Where `i` - the corresponding month of the year from 1 to 12;
Finding the solar share by months and on an annual basis is done in a similar way, applying dependencies from (4) to (12) incl. from the DHW model, in which case the load is calculated using the dependency (5).
In case the solar thermal installation has to cover the load for heating and DHW / mixed type installation, then dependencies from (4) до (12) are applied again, ncl. from the DHW model, but the load represents the sum of the DHW load and the heating load of the building.
The calculation of the required heat for a swimming pool depends on the following parameters: type of the pool (open or closed); geometric dimensions of the pool; desired water temperature in the pool; using a protective cover.
The load calculation methodology used is based on energy balance, not taking into account factors such as accumulated heat and raising the temperature of the water above the desired by the user.
For the calculation of the solar share by months and on an annual basis, the F method is used, which allows to estimate the share of heat generated from solar collectors in an installation without heat accumulation (Chapters 2 and 21, Duffie and Beckman (1991) et. all /.
According to the F method, solar thermal collectors will only provide useful energy when the intensity of the solar radiation falling on them is higher than any critical value. This critical value of solar radiation depends largely on the characteristics of the solar thermal collectors used and the temperature of the collector heat transfer medium.
In order to apply the F method, it is necessary to calculate the zenith angle of the sun, the angle below which solar radiation falls on the solar collectors, the ratio of the direct composition of the solar radiation on the collectors to that of the horizontal surface, the ratio of the solar radiation in the " solar noon "vs. daytime solar radiation, the ratio of diffuse solar radiation in the "solar noon" to the diffuse solar radiation for the day.
The calculation of the zenith angle of the sun is as follows:
| \[cosθz=cosφ.cosδ.cosω+sinφ.sinδ\] | (1) |
|---|
The calculation of the angle at which solar radiation falls on an randomly oriented surface is calculated by the following dependence:
| \[cosθi=sinδ.sinφ.cosβ+sinδ.cosφ.sinβ.cosA_{ZS}+cosδ.cosφ.cosβ.cosω-cosδ.sinφ.sinβ.cosA_{ZS}.cosω.cosδ.sinβ.sinA_{ZS}.sinω\] | (2) |
|---|
Where `A_{ZS}` is the azimuth angle of the randomly oriented surface.
The ratio of direct solar radiation on the collector to that of a horizontal surface is calculated as follows:
| \[Rb=cosθi/cosθz\] | (3) |
|---|
The relation of solar radiation in the solar nun with that of the day is calculated using the following dependency:
| \[r_{1}=\frac{\pi}{24}\left(a+b\cos\omega\right)\frac{\cos\omega-\cos \omega_{s}}{\sin\omega_{s}-\frac{\pi \omega_{s}}{180}\cos\omega_{s}}\] | (4) |
|---|
In which the coefficients a and b are calculated by the following dependencies:
| \[a=0.409+0.5016\sin(\omega_{s}-60)\] | (5) |
|---|
| \[a=0.6609+0.4767\sin(\omega_{s}-60)\] | (6) |
|---|
In dependencies (4, 5, 6) ω is the time angle for which the calculations are made, and ωs is the hour angle of sunset.
The ratio of diffuse solar radiation in solar nun to daytime is calculated using the following dependency:
| \[r_{d}=\frac{\pi}{24} \frac{\cos\omega-\cos \omega_{s}}{\sin \omega_{s}-\frac{\pi \omega_{s}}{180}\cos \omega_{s}}\] | (7) |
|---|
The ratio of solar radiation in solar nun on an inclined surface to that of the respective day of the month for which the calculations are made shall be calculated according to the following dependency:
| \[R_{n}=\left(\frac{I_{T}}{I}\right)_{n} =\left(1-\frac{r_{d,n} H_{d}}{R_{t,n}} \right) R_{b,n}+\left( \frac{r_{d,n}H_{d}}{r_{t,n}H}\right)\left(\frac{1+\cos\beta}{2}\right)+\rho_{g}\left(\frac{1-\cos\beta}{2}\right)\] | (8) |
|---|
Where `R_{b,n}`, `r_{d,n}` and `r_{t,n}` are calculated according dependencies (3), (7) и (4).
The average monthly measureless critical solar radiation is calculated using the following formula:
| \[\overline{X_{c}}=\frac{I_{Tc}}{r_{t,n}R_{n}\overline{H}}=\frac{F_{R}U_{L}(T_{i}-\overline{T_{а}}) // F_{R}(\overline{\tau\alpha})}{r_{t,n}R_{n}\overline{K}_{T}\overline{H}_{o}}\] | (9) |
|---|
Where
`I_{Tc}` is the critical value of solar radiation;
`F_{R}U_{L}` - the product of the collector heat output coefficient and the heat transfer coefficient of the collector, [W/m]2K;
`T_{i}` - тthe temperature of the collector incoming heat transfer medium, [°С];
`\overline{T_{a}}` - average daily ambient temperature, °С;
`F_{r}(\overline{\tau\alpha})` - The output of the collector heat output coefficient and the average optical collector efficiency;
`K_{T}` - the cloud factor for that month;
`\overline{H_{o}}` -
The average monthly usage coefficient of the solar thermal installation is calculated according to the following formula:
| \[\overline{\phi}=\exp\left\{\left[a+b\left(\frac{R_{n}}{\overline{R}}\right)\right] \left[\overline{X_{c}}+c\overline{X_{c}}^{2}\right]\right\}\] | (10) |
|---|
Where the coefficients a, b and c are determined by the following dependencies:
| \[a=2.943-9.271\overline{K_{T}}+4.031 \overline{K_T^2}\] | (11) |
|---|---|
| \[a=-4.345-8.853\overline{K_{T}}+3.602 \overline{K_T^2}\] | (12) |
| \[a=-0.170-0.306\overline{K_{T}}+2.936 \overline{K_T^2}\] | (13) |
The useful energy obtained from the solar thermal collectors for the respective month is determined by the following dependency:
| \[Q=A_{c}F_{R}\left(\overline{\tau\alpha}\right)\overline{H}_{T}\overline{\phi}\] | (14) |
|---|
Where:
`A_{c}` is the area of the solar thermal collectors in the installation, [m2];
`\overline{H}_{T}`- the average daily intensity of solar radiation in the solar collector plane;
According to (14) we get the energy per one day. Accordingly, for a month it is necessary to multiply the result by the corresponding number of days in the month.
The required heat to maintain the water temperature in the pool at the desired level is calculated on the basis of energy balance. For this purpose, it is necessary to determine the heat gains and losses.
Thermal gains per day depend on the geometric dimensions of the pool, the presence of shading elements such as trees, buildings, and so on. and the use of a protective coating.
It is necessary to note that there is no thermal gain for indoor swimming pool / inside a building.
| \[Q_{p}=\left[\frac{N_{no,b}}{Day_{L}}\cdot Q_{p}\cdot no, b+\left(1-\frac{N_{no,b}}{Day_{L}}\right)\cdot Q_{p,b}\right]Days_{i}\cdot F_{m}\] | (15) |
|---|
Where:
`Q_{p}` are the total heat gains for that month, [MJ];
`Day_{L}` - the duration of the day for that month, [h];
`Qp.no,b` - thermal gains in the absence of a protective cover, [MJ/ден];
`Q_{p,b}` - thermal gains with an enclosed protective cover, [MJ/ден];
`Days_{i}`- the number of days in that month;
`F_{m}` - pool utilization rate for that month;
Heat losses from evaporation are calculated by the following dependence:
| \[Q_{e}=\left[Q_{e,off}+Q_{e,on}\right]Days_{i}.F_{m}\] | (16) |
|---|
Where:
`Q_{e}` are the total heat losses from evaporation for the respective month;
`Q_{e,off}` - the total heat loss from evaporation per day when the protective cover is removed, [MJ/ден];
`Q_{e,on}` - the total heat loss from evaporation per day with an enclosed protective cover, MJ/ден;
`Days_{i}` - the number of days in that month;
`F_{m}` - pool utilization rate for that month;
The total heat losses from evaporation per day when the protective cover is removed are calculated according to the following dependence:
| \[Q_{e,off}=he\left[P_{s,w}-P_{a,w}\right]\cdot24\cdot\left[\frac{24-N_{b}}{24}\right]\cdot A_{p}\cdot F_{a}\] | (17) |
|---|
Where:
`he` is the coefficient of evaporation from the water surface, [kg/m2Pa];
`P_{s,w}` - saturation pressure of water vapor over the water mirror, [Ра];
`P_{a,w}` - partial pressure of the water vapor in the air above the water mirror, [Ра];
`N_{b}` - hours of the day when the protective cover is placed;
`A_{p}`- area of the water mirror of the pool, m2;
`F_{a}` - a factor that measures the activity of the pool users;
The total thermal losses from evaporation with a placed protective cover per day are calculated according to the following dependency:
| \[Q_{e,on}=he\left[P_{s,w}-P_{a,w}\right]\cdot 24 \cdot \left[\frac{N_{b}}{24}\right]\cdot A_{p}\cdot 0,1\] | (18) |
|---|
The coefficient of evaporation from the water surface is calculated by the following dependence:
| \[he=0,05+0,07\cdot W\] | (19) |
|---|
Where W is the average wind speed immediately above the water mirror, [m/s].
Heat losses from convection are calculated by the following dependence:
| \[Q_{c}=\alpha \left[tw+ta\right]Ap\cdot Days_{i}\cdot F_{m}\] | (20) |
|---|
Where:
`\alpha` is the coefficient of heat transfer from convection,[W/m2K];
`tw` - the temperature of the water in the pool, [К];
`ta` - the average daily air temperature for the respective month / respectively the air temperature inside the building is taken for indoor pool/, [К];
`A_{p}` - the area of the water mirror of the pool, m2;
`Days_{i}` - the number of days in that month;
`F_{m}`- the rate of use of the pool for that month.
The coefficient of heat transfer from convection is calculated by the following dependence:
| \[\alpha=5,7+3,8\cdot W\] | (21) |
|---|
The loss of heat from the water mirror as a result of radiant heat exchange is calculated by the following dependence:
| \[Q_{r}=Ap\cdot5.67\cdot 10^{-8}\left(9,96\cdot\left[\frac{24-Nb}{24}+0,456\cdot\frac{Nb}{24}\right]\right)\left[tw^{4}-ts^{4}\right]24\cdot Days_{i}\cdot Fm\] | (22) |
|---|
`tw` - the temperature of the water in the pool, [К];
`ta` - the average daily temperature of the sky for the respective month / in indoor pools is adopted temperature of the sky 293,15К/, [К];
The loss of heat from replenishment of the pool is calculated by the following dependence:
| \[Qm=Qm,d\cdot Days_{i}\cdot Fm\] | (23) |
|---|
`Qm` - the energy needed to preheat the cold water to replenish the pool for a month, [MJ];
`Qm,d` - the heat energy needed to preheat the cold water to replenish the pool for a day.
The energy required to heat cold water per day is calculated by the basic calorimetric equation, as for the water temperature of the water-main the average water temperature of the water-main for the respective month is taken. The amount of evaporated water per day is calculated as daily evaporation heat losses are divided into latent heat of evaporation of water, which is a function of the pool water temperature and atmospheric pressure, which in turn is directly related to the altitude, on which the pool is located.
Heat losses through the bottom and pool walls are calculated using the classic methodology used in buildings to determine the heat transfer coefficient of the floor and walls bordering on the soil. Accordingly, the heat loss is obtained as a product of the respective heat transfer coefficient, the area of the respective element and the temperature difference. The temperature difference is the difference between the water temperature in the pool and the average daily ambient air temperature for that month.
The total heat loss from the pool is the sum of all the losses listed above.
The energy required to maintain the water temperature in the pool at the desired level is calculated as a difference between total heat losses and heat inflows.
The solar fraction of the solar thermal installation for the respective month represents the ratio of the heat generated from the collectors divided by the energy needed to keep the water temperature..
The additional energy for the pool is the difference between all the energy to keep the water temperature minus the heat generated by the solar collectors for the respective month.
Solar Thermal Calculator
Manufacturer: Темпус-2000 ООД
Serial number: SDP–2614–3916–STSE
Version: 2.1.0.0
Date: 11/29/2022 12:40:50 PM