Solar Water Heating Technical Adviceby Admin
Oct 2013

Message: Dear Team,   I need some technical advice, I am a mechanical engineer and i have a commercial project which requires heating about 8,000 gallons of water in a tank from a temperature as low as (15C or 60F) till it reaches (70C or 155F), However space might be a limiting factor. My question is how much space would i need to place high efficiency solar collectors (Plates or Tubes) and how much would it cost approximately. if this project works I am thinking of opening my own company only for projects involving solar water heating for commercial or domestic use. it would be great if you can also separately provide the prices for accessories and other parts that i might need to propose for this project.   Best Regards, Sayf Khasawneh

Dated on : 07-29-2012


Replies :

As a mechanical engineer you would have the training to calculate the energy required to raise 8000 IMP gallons of water 95 degrees F (answer is 7,600,000 BTU).  It now becomes a matter of how long you are willing to wait to obtain this amount of energy.  Does it have to be done in one day?   Say, as an example the answer was yes, you wanted the water to be heated up in 8 hrs . In that case you would need to deliver on the average  960,000  BTU/hr .  A  30 tube solar collector measures 94 x 78 inches.  It will have  peak output of about 2 kW (~6800BTU/hr), averaging 1.5 kW (5100 BTU/hr) over the better part of the day.  Power drops to about 1/2 on a cloudy day.  If you complete the mathematics, it would be a very large number of collectors.  Likely not practical, for you. Perhaps what is more practical is raising the water using a natural gas heater but maintaining the temperature using solar.  Now you only have to supply enough energy to match the heat loss and that depends on the insulation and on the rate you use up the hot water.  In this case you already have invested in the natural gas heater and you would have to determine if the added cost of the solar collectors and the controls and circulation system gives you a sufficient return.   Dieter Jung   Northern Lights Solar Solutions

Post By : Dieter Jung Dated On : 07-29-2012

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