I've been thinking about this one for a while, but the old house had
city water and with that, a city sewer bill. The new place has a well and septic. I can pump water until the ground caves in and the only bill would be the electric to run the pump. This makes my idea a little more practical...
SPACE HEATING AND COOLING WITH HOME AND IRRIGATION WATER USAGE
In northern Florida, water from the well comes out of the ground at about 65 degrees, even in the summer. If the water can be directed to flow through a radiator with a fan moving air though the radiator, the air temperature would change to be closer to the temperature of the water, offering heat or cooling to whatever space into which the air is then directed.
Summer
Air temperatures reach some gawdawful highs in the summer, 93 is the average daily high for 3 months a year. I'm a tightwad, so I keep the AC set at 80 degrees and only turn the thing on when I'm home and inside. With a system in place as described above, the cooling effect would not be sufficient for more than a couple of small rooms. Air humidity often is in the 80-90% range every day. A significant amount of condensation can be expected on the radiator coils. This would have to be addressed to prevent property damage.
Water demand of crops in the summer is high. With a sandy soil that drains rapidly and an unrelenting sun directly overhead, irrigation is often required to support crops.
Winter
Although I have yet to see snow in the winter after 11 years in North Florida, I hear tell from those that know that it is not unheard of, occurring with slightly more frequency than Loch Ness Monster sightings. Nonetheless, January will see nighttime temperatures dip into the 30s and even the 20s. We get a few frosts each year.
I like to be warm. I have proven this to my satisfaction. 65 degree water as a heat source will not be sufficient to heat my home to my level of comfort, but it would go a long way toward heating a garage, barn,
greenhouse or
workshop to an acceptable level. Since the air moving through the radiator will be cooler than the radiator, considerably less condensation is expected.
Water demand of crops in winter is still high. Crops can be grown all year in this climate, but winter is the dry season. Rainfall is light. Even with rain, the soil does not hold water.
Numbers
Lets put some math behind the idea and see how effective such a rig can be.
Drip irrigation tips generally operate with a flow rate of 1-2 GPH and a head pressure of 25 PSI. A typical well around here can offer up 50 PSI at a flow rate of 3-4 GPM. My water pressure is awful, but it is possible to do some tweaking to improve that situation. Assuming I am handy
enough to get the job done, an ultimate flow rate of 250 Gallons Per Hour is not unreasonable.
Water weighs 8 pounds per gallon.
250 gallons per hour moves 2000 pounds per hour.
If the device described above is able to transfer just a 10 degree difference in temperature, the amount of
energy transferred would be about 20k BTU/hour.
A fair sized window air conditioner would have about the same amount of cooling ability.
A couple of small electric space heaters would have about the same heating ability.
More extreme temperature difference between the air and the water would result in greater effectiveness. The system would have to be big enough to handle the water flow. Air flow could also be adjusted. The system can be expanded in complexity to include whatever automatic parts are needed: sensors, thermostats, sequencers, even zones could be setup if there is sufficient water and/or airflow. There are 2 moving parts: well pump and air fan. The whole thing could be run on
solar PV.
Next thing to consider is what to do with the 250 gallons per hour moving through the rig. This is 6000 gallons/day if running wide open 24/7. If 1 gallon of water can service a 4'x4' area of bed (double dug raised, hugelkulture, or even the equivalent area of containers), the capacity of the system would service 96000 sqft per day. Man, tha'ts a lot of celery. If the cultivated area is 50% of the total field, 4' beds with 4' paths, the field would be 4.4 acres.
This 6000 gallons is what comes out of the well. Some is used for washing dishes, some for bathing, cooking, using the john, watering the
chickens and pigs. Also, the system does not need to run when its raining. There are plenty of things that can be added, for example, holding tanks-let the water cool down or warm back up before heading to the field, as well as provide a buffer for use today and distribution tomorrow.
The technology required for this system exists and is readily available for reasonable (but surely not free) costs.
Discuss.