Zach, the site is at roughly 3200' and 35 degrees N., in the high desert of California, north of LA.
Because of the altitude and other climate effects they get
alot of sun year-round and have a large swing in diurnal temps. both in the summer and the winter. My gut feeling is that ventilation of high day time temps is going to be the biggest challenge. The plan is to moderate day time heating by storing it in the AP system, the thermal mass along the north wall and good venting. Ideally I would like to sink the whole thing a feet few blow grade as well as berming the north wall.
The idea of using earth tubes in the CRMPI style has also been a possible design consideration. I like the concept but the calculations for a
greenhouse of this size requires big fans, lots of tubing and power... I am not totally sold on it. Do you have any
experience with their technique? Or other thoughts on earth coupling, either for cold air intake or thermal storage?
Thanks for the info on the glazing, crop
plans have not yet been determined but the designed AP system is weighted towards producing leafy greens in floating rafts. I am thinking that I would like to use glazing on the upper half of the walls to the south and let the earth berming wrap around in the north. Insulating all along the bottom half and using onsite sun angles to determine where to start with the glazing going up.
Along that line, have you used Solexx? What are some of your preferred materials for glazing? I would like to use old sliders but the remoteness of the site will make this difficult...
I think that we are going to need shade cloth in the summer regardless of other strategies and maybe designing a roll up system that can be switched between summer shade and winter insulation would be pretty cool...
I like to go with
native fishes for my projects as much as possible. Sturgeon will be the main species in this system.
Water is heated solely through
solar gain. The design also includes black 55 gallon barrles stacked 2 high along the north wall. The shallow (12") troughs pick up heat really well and when circulated to a sunken tank it becomes a very effective thermal mass. I have been thinking of backup systems for heating, I have used
compost heating (Jean Pain method) for domestic water heating before and had good results so I think that stacking these functions would be a great fit. I also have had good luck using flat coiled black poly pipe laid out on the earth...
I am really curious about the balance of thermal mass. At what point is it too much? The mass will moderate temperature swings but when does it begin to hold too much heat, losing the ability to effectively cool off in the nighttime? Do you have a formula or work through for this?
Thanks for your responses and time on this.
J