Navitron Renewable Energy and Sustainability Forum

WIND TURBINES => Direct Heating Systems => Topic started by: alfier on September 28, 2013, 05:46:12 PM

Title: What heat store for UFH
Post by: alfier on September 28, 2013, 05:46:12 PM
My son has just put in to his electric only flat!!PLUO303!!/X005004001/Underfloor%20Heating/Polyplumb%20Underfloor%20Heating%20House%20Packs/Polyplumb%20Overlay%20House%20Packs/Polyplumb%20Overlay%20House%20Packs%2030m%3Csup%3E2%3C/sup%3E/Polypipe%20UFH%20Overlay%20House%20Pack%2030m%3Csup%3E2%3C%2fsup%3E,%203%20Circuits%20O303

He now needs to find a boiler/Hot water tank that will supply hot water to the under floor system only using economy 7 topped up with day electric if required. Any ideas?

Title: Re: What heat store for UFH
Post by: dhaslam on September 29, 2013, 01:49:31 AM
There are two pieces of information needed, the estimated  daily heat requirement and   the space available for a store.    Electric elements can  heat to a high temperature  but  high temperatures can increase losses from the store. The product referred to seems to use  about 3 kW, ie. 3X 15 sq metres at 70 watts/sq metre.    If you take  a temperature  range of 40C  from 70C down to 30C    the tank would need  about 65 litres for every hour at full output.   The calculation is  860  X 3 kW /  40 degrees   =64.5.   

Title: Re: What heat store for UFH
Post by: chasfromnorfolk on September 29, 2013, 09:35:54 AM
Hi Alfie, I can't open the link, but I guess from it, your ref to a boiler/tank plus dhaslam's reply it's a wet underfloor system we're talking about.

Until early this year I ran my 60m2 of underfloor on an Aztec 6Kw boiler

having no other heat source at the time.
If the mass of the floor the heating's installed in can be seen as a store in this case, your son may find as I did that with E7 over night to warm the place up plus thermostat-controlled use at other occupied times it may work economically without a store. In a flat there may be something to be said for trading the (possible) extra efficiency of a big old store with the tiny wall-hung Aztec bunging the heat straight into the floor where you want it.