Rainwater Harvesting for Residential Heating and Cooling

The key thing is system cleanliness. Water at ambient temperatures is a wonderful medium for biology to thrive in, which is the exact opposite of what is wanted for domestic heating/cooling systems, so they need biocides and antifoulants.

Hi,

BS EN 1264 is usually used for undefloor heating. I would like to know which formulae I can use for underfloor cooling since my design would be both for cooling and heating.

Thanks

There is a lot of information on in floor water heating.

This is my results from a Google search.

My sister has had in floor water heating for years and loves it.

I hope this helps.

SunTouch Warm Floor http://www.warmyourfloor.com wire heat cable is an economical solution for an electric radiant heated floor to warm tile in small or large areas. Warm Wire lets you customize a layout around curves, angles or objects and choose 10, 12 or 15 Watts per SF of heat

why rainwater harvesting? this job is normally done in a closed cycle, rainwater harvesting is normally used in an open cycle. Why rainwater for this application?

Hi,

Thanks for your response. In fact, I put in place this system as a sustainable development project. The use of rainwater is a cheap source, the water will be stored and treated prior to filling the underfloor pipes. It will be a closed circuit.

Regards,

Surjun

Hi,

in fact I think Surjun's idea can be extended to use rainwater in an open circuit for air conditioning.

Why use rainwater? Rainwater temperature can be much lower than ambient temperature. Using rainwater to cool your condenser would increase efficiency.

I have used rainwater in Manaus (almost equator) to feed a cooling tower. After the 3 p. m. rain the blower could be shot down for some time. Algae must be controlled anyway.

In floor cooling does not work! Cooling the floor will only make a damp slippery floor. Plus cool air is denser so it will stay on the floor. You will get cold wet feet and not much else.

The volume of water needed to cool a house will be far more than a rain storm can produce. I'm not sure where your at but when it rains here the air is cooled down outside. So just open a window to cool the house off! Its faster, far more efficient and simpler too!

One pound of water takes 1 BTU to raise its temperature 1 degree Fahrenheit. 1 gallon of water wheighs 8 1/3 pounds. A typical home around here has a 24000 - 36000 BTU air conditioning system. And can run 10 or more hours a day. Plan to capture and transfer tens of thousands of gallons of water for just one days cooling! You better have a big swimming pool and insane amounts of very cold rain every day!

A water based heat transfer system does not take much water. Just use a bucket and get it from a near by town that has treated public water systems if you don't already have it at your home. A large house 2500 (square feet) takes less than 40 gallons. I use far more than that in one day just from normal life uses.

Dear Tcmtech,

floor cooling is out of question for the reasons you point out, no matter what your "cold source" might be.

I do not intend to cool a house with rain water directly. But I could cut my power bill by cooling my AC condensers with rain water.

I'm at 30 deg south, 50 east (subtropical region). This is where a lot of cold air coming from the south pole meets the hot and moist air flowing down from the amazonic region. It rains a lot, our state's name means "Big River in the South".

Opening windows after the rain is fine during spring or fall... but in the summer the air outdoors will be hotter and close to 100% RH!

Many home owners balk at the idea of fitting rainwater harvesting because of the problems involved in getting a 5000 litre rainwater tank through those narrow Victorian doors and stairways into the back garden. But the new race of tanks that come as two shells which get fixed together on site have done a lot to ease this problem.

"We have been able to install our rainwater harvesting with no professional help at all. For Ron and me, two people who have got limited DIY skills, this has been achievable. When it comes to electricians, plumbers, plasterers, I'm going to hand that on to somebody else. By doing the work now, we get free water for years and years to come. Each time we flush the toilet and wash our clothes, we are able to look towards the sky and say "Thank you. You know; free water! Great."

Greentech are specialists in a range of Rainwater-Harvesting Services.

Surjun,

Have you developed on this idea?

I'm living in Laos which has a Monsoon and was thinking along similar lines in terms of finding a heat source at lower then ambient air to provide air conditioning. I was thinking of using the stored water as a heat exchanger for a heat pump.

Was also wondering of potential of cooling the stored water via a heat exchanger on the roof of the house at night when air temp is often 10 degrees lower.

Hoping that this idea may have potential in terms of sustainable lifestyle as air con makes life easier in the Tropics but is heavy on electricity when ambient air is mid to high 30s.

Rich