solar hot water- high standby losses in secondary boiler loop


  #1  
Old 07-02-14, 12:50 PM
S
Member
Thread Starter
Join Date: Jul 2014
Location: canada
Posts: 3
Received 0 Votes on 0 Posts
solar hot water- high standby losses in secondary boiler loop

Hi guys- new to forum.
I am trying to get my solar hot water system working. The contractor walked without finishing the job. Indirect solar heating with solar glycol loop. Lots of heat generated 250 to 300 deg F in the solar glycol loop. Transferred to a secondary water loop through a heat exchanger and circulated by a grundfos pump. Stored in this loop in two 60 gal storage tanks. Water heats up in tanks to 140 during the day(10am to 7pm) then cools to 127 by morning. Aquastat turns on circulator when temp reaches above 140 to cycle water from the storage tanks to the boiler primary loop and back to the loop before the circulator. Grundfos pump in boiler loop set at a higher flow than secondary loop. Cycle continues without providing enough hot water to the boiler loop to heat my hot water tank which is on another secondary boiler loop. My hot water tank is heated by the boiler when solar does not provide enough heat and has standby losses of 1 deg per evening. I drained air from this loop at the highest point above the storage tank. Grundfos pumps have check valves in them. Don't know why the tanks don't heat much above 140 F. and why the standby losses are so high. They should be about 1 deg per evening. Can anyone help.
Thanks
DD
 
  #2  
Old 07-02-14, 04:39 PM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
I doubt there are many people here with technical experience in those systems. Who manufactured the equipment? Those are the people whom I would contact.
 
  #3  
Old 07-02-14, 05:33 PM
S
Member
Thread Starter
Join Date: Jul 2014
Location: canada
Posts: 3
Received 0 Votes on 0 Posts
Thanks... I found a good article on primary/ secondary and multiple boiler systems at Laars Heating Systems: High Efficiency Residential and Commercial Boilers, Combi Boilers, Water Heaters and Pool Heaters | HOME which helped me understand the system and how it works. The devil is in the details. Guess I will have to find a hydronics engineer.
 
  #4  
Old 07-02-14, 06:47 PM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
I don't think that you need an engineer. I think that you need a factory representative.
 
  #5  
Old 07-03-14, 10:36 AM
S
Member
Thread Starter
Join Date: Jul 2014
Location: canada
Posts: 3
Received 0 Votes on 0 Posts
The system includes a micron electric boiler in the primary loop which works well to heat my hot water. There is a grundfos pump and air extractor in the system as well as an inlet for water and an air bladder tank. The secondary loop from the solar hot water heat exchanger has a grundfos pump and two water storage tanks as well as an air bleed unit. Pretty simple stuff when one breaks it down.

Thanks...I can try and call the manufacturer of the water storage tanks. They may have an idea of why the tank does not heat much above 140 F.
dd
 
  #6  
Old 07-03-14, 07:13 PM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,982
Received 0 Votes on 0 Posts
What about the manufacturer of the entire system, not just the tanks?
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: