Heat pump help with cold pumping

7 July 2013: The hottest day of the year and Murray is slugging it out with Djokovic and Wimbledon! Meanwhile, I am keeping an eye on my solar earth charging circuit.

The ETFE Sunbox fronts are so effective that the temperature in main Sunbox (Surya-3) has risen to over 70ºC! This is far too hot and I need to find a way to reduce it. Liquid flow of 160 litres per hour is just too slow to remove this heat, so I have turned to the GSHP to circulate cold. The pressure of this pumping pushes more liquid up to the loft area if there are two small pumps up there pulling it along.

When the powerful pump in the GSHP is cold-circulating, the assistance it gives to circulation is enough to boost the flow rate more than 3 times, to 490 litres/hr. It boosts the kilowatt rate to over three, and lowers the highest temperature in the Surya by 30 degrees - that gets the heat down more quickly and enables the black panels to accept more solar energy.

The power used by the GSHP is immaterial because in this sunshine, it is being driven by the large Photovoltaic array on the roof!
    I know what my evening project is!

• I have to swap the recently-purchased faster pump to the Surya 4 circuit
• Modify the heat exchanger circuit for the Tubes to have less flow resistance, and return the Tubes to using the weaker pump.