Five Aces Breeding LLC

The Strawberry House.

Construction specifics:

25 x 23 ft footprint

Bottom 32 inches (48 inches on the north side) consists of FoxBlocks insulated concrete forms (11 inches thick: two  2 5/8 inch thick Styrofoam sandwiching 6 inches of plastic and steel rebar inforced concrete. The outside of the blocks was waterproofed with blue sealant paint and exposed bits stuccoed.

The floor was poured concrete.

The aerial construction was 2 x 3 inch steel tube and 10 mm twin wall clear polycarbonate sheet (South, East and West walls) or for the north wall, 1/4 inch (to allow bending)  plywood  sandwiching  multiple layers of blue insulation board for an R value of 12.  The steel tube was from a 15-30-75 degree angled set that was designed for construction of stand alone carports (the kind with g rib sheet metal).  The combination of angles and swagged ends allows (with extra parts) reforming the structure to a nice small greenhouse which has a long span which must be supported with posts.

A 1100 gallon reservoir (on the right in the picture above) was constructed out of FoxBlocks and lined with a pondliner (AZ Ponds).  In our initial runs, we lost 5 F and 7 gallons of water every night to evaporation. In this case an unwatched pot slowly boils. We solved this by floating stiff blueboard insulation (1 inch thick) on the surface of the water.

An 8 ft x 20 ft wide FAFCO solar water heater was mounted at 65 Angle from horizontal and facing sun this fixed angle was designed for highest heat through the entire day for the winter solstice.  The solar collector was donated by FAFCO (Chico CA) through their distributor, Harris Pools. Water circulates through this only when the temperature of the collector is 3 F higher than that in the reservoir. The water is pumped with a residential pond pump at approximately 100 gallons per hour (8 ft head).  When the pump is off, a release valve at the top of the collector allows water to empty from the collector to reduce the possibility of water freezing in any of the tubes and pipes.  All supply pipes were pitched at 6 inches per 10 ft. downward toward drains.

The heat of the reservoir water is dissipated in the greenhouse when the temperature is <55 F through twin GMC truck radiators. The radiators are fan cooled and the water is pumped through automatic dish washer tubing using a residential fountain pump (330 gal per hour, 11 ft head).

Twin 130 ft long 6 in diameter black corrugated drain pipe (no holes) earthtubes were buried 5 to 6 ft underground which was then covered with 3 ft of fill to level our outdoor graveled nursery beds. Both tubes were run from the greenhouse to a small inlet under the forest canopy.  Unfortunately a heavy rain flooded one of the tubes and it had to be destroyed.  We buried a replacement tube to 4 to 5 ft deep in a closed racetrack fashion. This 4 inch diameter tube picks up air from the floor of the greenhouse and returns to the greenhouse with the other tube in a box behind the second truck radiator with solar heated, reservoir, water. A squirrel cage fan draws air from the earthtubes past the radiator.  I hate to admit this, but the fan is too powerful at 1000 cfm and the resistance of the tubes is extraordinary.  Air flow is at least 3-6 mph, but a lot of energy is wasted. The corrugated pipe, as you might figure, not conducive to quick airflow (it is cheap).

Discussion of cooling.

The earthtubes do really provide about 200 to 300 cfm of 60-70 F air in the middle of the summer for us. I wish I had about 5 of them -live and learn- I could make a dent in the temperatures in the greenhouse then. 

The solar heating system reservoir does provide an interesting alternative to my cooling problems.  Being at the top of the mountain does provide for quite a bit of cooling capacity in winter.  We use water to evaporative cool in summer, and although that is very efficient, I don’t want to humidify my houses. Instead, we have, and we can manufacture in outdoor ice cube trays- at no energy input, plenty of ice here.  Ice melts and uses 80 cal/g of ambient heat in the process.  In addition, the melted water is at 32 F and takes an additional 20 cal/g to warm to 72 F.  Doing the math, 15 gallons of ice per day in the reservoir would provide 10,000 BTU of continuous cooling.  For 100 days of cooling, or 1500 gallons of ice, I’ll need approximately an area 200 cubic feet (4 x 5 x 10 ft). Double this size for melting loss, we have the size of my new refrigerator, or my old icehouse. Thus, this year’s trials will include a competition between the straw bale/OSB icehouse and the insulated concrete form refrigerator (no compressor used to make it fair). I may try to freeze the water in gallon jugs if we get another 266 inches of snow!