Help sizing solar thermal install!

[westyvip]

Hi, i am installing solar thermal panels on a house i have just bought. It is a 3 bed semi and im struggling to decide what size system to install! I understand that 1m2 per person.....with only two of us in the house....2m2 is adequate. However, should i take into consideration the size of house and potential for more occupants?

 

[Gray0689]

I'd go for a 20 tube kingspan thermomax (but if you want to go for slightly bigger them go for 30 tubes)

 

[tm plumbing]

As a rule of, systems for supplying hot water are configured to yield a percentage solar contribution of 50-60%. To estimate the size of the system you can use the following values as a guide:

• Collector surface area: 1.0 - 1.3m2 / person
• Storage cylinder size: 50 - 60 l/m2 collector surface area

Trev TM Plumbing​

 

[core heating]

agreed with TM plumbing to a degree. although i always go slightly over. the extra outlay for that extra panel is worth while . the main expense is already done so for the sake of 500quid at this stage is worth it, if you have space on roof

 

[wiggers1]

I would size the collector to the cylinder. Over sizing the collector would be great in the winter but will cause stagnation problems during the summer if you dont draw off the hot water. During summer an over sized collector can over heat the glycol, the glycol expands and the pressure builds. At +6bar it will blow out into the discharge vessel. When the system cools the loss of glycol results in the the system registering zero pressure and needing re-pressurising to 1bar.
The glycol can cope with high temps but continuous exposure to very high temps will break down its properties and it will need changing more frequently.
There are solar suppliers that will size your system for free and provide a professional energy calc. PM me for more info.

 

[BLOD]

Can't see the problem in over sizing as long as you've built in a suitable heat dump.

 

[eaton]

I'd go 210-250 cylinder if unvented and 2 panels or 30 tubes. Give Barilla solar a call

 

[Gray0689]

210 to 300ltr 30 tubes kingspan thermomax