Pool heating
First of all: It is important not to overdo the temperature of the water in the pool. The high temperature of the water in the pool can cause illness. All germs develop much faster at higher temperatures.
Second of all: Heat losses are very important (for example, the difference in temperature between the water and air, thermal insulation of the pool from the ground, pool surface, etc.). If the ambient temperature is higher than the temperature of water in the pool, there will be no heat loss to the air. Losses can still occur into the ground.
1. Solution: use of non-pressure collectors connected to the filter pump circuit.
Advantages: lowest cost.
Disadvantages: The water is heated only when the filter pump is working (plus additional 50 liters of water in one collector).
The collectors from the JNMK series compared to JNSC collectors (and other collectors from different manufacturers based on heat-pipes) are made entirely of stainless steel. Also, the heat exchanger in the bus bar at the top of the collector is made of stainless steel inside and has a larger connection diameter (1 inch), which will allow for greater water flow.
You can pass chlorinated pool water directly through such collector (you do not need to build complicated heat exchangers and closed systems working under pressure on a glycol solution). Due to the fact that they are non-pressure collectors, they are much cheaper than those from the JNSC series (or other collector models from other manufacturers).
The active area of the absorber of one JNMK-20 collector is: 2.48 m2 (heating power 1.7-2.4 kW -of course, depending on the exposure to the sun).
To heat 1 liter of water by one degree you need 4200J, that is, 0.001166666667 kWh.
For example, a swimming pool contains 10,000 liters of water (10 m3). To heat it by 1 degree, 11.66 kWh is needed.
One JNMK-20 solar collector will generate around 17 - 23 kWh during a sunny day (which means it will heat the water in the entire pool by about 1.5 degrees C).
It means that:
- two such collectors will raise the temperature by about 3 degrees C.
- ten such collectors will raise the temperature by about 15 degrees C. and so on
- One vacuum tube has a maximum power of 0.12 kW
- to heat 10,000 liters of water (10 m3) by 1 degree C, about 100 vacuum pipes (12 kW) are needed
- to heat 20 000 liters of water (20 m3) by 1 degree C, about 200 vacuum pipes (24kW) are needed
- to heat 5 000 liters of water (5 m3) by 1 degree C, about 50 vacuum pipes are needed
2. Solution: use of pressure collectors (on heat-pipes) for example, from the JNSC series, connected to a separate circuit connected to the heat exchanger in the pool.
Advantages: The collectors work independently of the filter pump.
Disadvantages: Very high cost of equipment. The water in the pool is only heated when the circulation pump is working (without any additional buffer).
The heating power of collectors based on heat-pipes (regardless of whether they are our collectors from the JNSC series or collectors from other manufacturers) will be comparable with the heating power of non-pressure collectors from the JNMK series. However, the much higher cost of buying collectors, additional circulation pump, and heat exchanger in the pool makes this solution the least profitable. The only advantage of such a solution may be the possibility of working such a system on a glycol solution that can remain in the system during the winter. When using non-pressure collectors working on the water, it will be necessary to drain the water for the time of winter.
3. Solution: use of compact non-pressure collectors from the Solaris-L and JNYL series.
Advantage: The cost is slightly higher than when using JNMK collectors, a large supply of hot water that is discharged into the pool before swimming (which prevents it from cooling down)
Disadvantage: The only disadvantage is the need to drain the water from collectors for winter.
In addition to the slightly higher cost of purchasing equipment compared to the first solution, we get a number of other benefits:
- a large stored buffer of warm water, which does not cool during the day and is "discharged" into the pool before swimming
- the system does not constantly load the filter pump (collectors are emptied by gravity, filled once a day using a separate pump or a filter pump).
The energy balance (when using a 20-pipe solar collector) will be the same as in the first solution, but we will avoid unnecessary cooling of water. You can, for example, heat the water in the pool at night or in the morning (which will be impossible in the case of the first or second solution).