Solar Water Heating Storage Options

 
SOLARUSES

Particularly for larger installations, the efficiency, cost-effectiveness and overall ability of a solar heating system is completely dependent upon sound design knowledge and experience. Contact VM today to discuss the design process.

 

NOTE: The information presented in this page is for guidance only - no part of this may be used for any agreement, whether express or implied, or to form any contract. THERMO TECHNOLOGIES reserves the right to change specifications and prices without prior notice.


Storage For larger installations, two or more tanks may be connected to the collector arrays as illustrated:

How the system works
Depending on temperature level of tanks, pump 1, 2, or 3 will run.  If water temperature in the tank 1 is lower than a setting point TR1 (T1 <= TR1), only pump 1 is running. Whenever the tank 1 setting point (T1>TR1) reached, pump 1 stops and pump 2 starts. Once tank 1 and tank 2 have reached their set points, pump 3 starts and so on.
The advantages of the connection are:
1) The preheat tanks can be easily isolated for the purpose of maintenance. This is very important for commercial hot water supply systems.
2) Temperature levels for preheat tanks can be easily controlled. The developed thermal stratification from tank to tank can reduce heat losses and subsequently, improve the performance of the entire solar energy system.
It should be noticed that for commercial hot water service systems standby pumps are normally required, which means more than three water pumps may be needed for the solar system with three storage tanks.
   
Recirculation loop approach is suitable for existing commercial hot water service systems, for instance, in hotels, sport clubs, hospitals, and schools, etc. A solar collector subsystem can be integrated into the hot water return loop. The schematic diagram of the layout is presented below.
   
 
   
  Hot water return from the domestic hot water circulation loop is diverted by a three-way motorized valve, depending on the temperature difference Tc (collector temperature) and T (water temperature return from the load), Tc - T. When the temperature difference is higher than a preset point, water from the load will be passed through the collector loop and then flows into the storage tank. Otherwise, the motorized valve will divert water from the load directly into the storage tank.
During potential freezing conditions, for
instance, when the temperature drops below 40 ºF , the system controller can energize the collector pump to cycle water through the collector loop.
   
 
   
In a simplified solar  water heating system (see the Mid Atlantic Social Security Center Solar Water Heating ) a pump forces the circulation through the solar array when the temperature difference Tc (collector temperature) and T (water temperature in the bottom part of the tank) is higher than a presetting point.

 

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