Building A Solar – Heated Pit Greenhouse Storeys Country Wisdom Bulletin A – 37 – Greg Stone

I dug a 16-inch ditch around the perimeter. In that ditch I used a post hole digger to dig six-inch post holes down to below the frost line. These were on three-foot centers. I poured concrete into the six-inch holes, then, when the concrete had hardened, I completed the piers by placing a concrete block on top of the concrete posts. The boards of insulation were placed between the posts, and the dirt shoveled back around them. A warning: take a lot of care in making certain the piers are level with one another.

The height of the pier can be adjusted a bit by varying the thickness of the mortar joints. When ready to put the anchor bolts in place, fill the holes in the concrete blocks with concrete, let it begin to set, then put the anchor bolts in place, leaving enough protruding so that they will extend through the sill, and a nut can be placed on them.

It’s necessary to have all piers at the same level if the 2×6 sill is to fit correctly. Into the top of each pier cast an anchor bolt of ½″ × 8″. Make sure it is positioned correctly. Drill holes in the 2×6 sill for the anchor bolts and attach the sill to the piers.

The rest of the greenhouse will be attached to the sill. Instead of digging a full-sized pit, I dug a center aisle, two feet wide and four feet deep which ran the length of the greenhouse minus 3 feet for the bench opposite the door. In the bottom of the pit went a one- foot layer of gravel. The sides of the trench were shored up with a framework of 2×4’s sheathed with ⅛-inch asbestos cement board. The excavated dirt was later used to make an insulating bank against the north wall.

Soil Benches The rest of the soil surface became my “benches.”

If you’ve always wanted a greenhouse, but you’re scared off by the high cost of energy, take a close look at the solar pit. It’s a greenhouse that combines the energy-conserving features of the traditional pit greenhouse with some newer techniques and materials used in modern, heated greenhouses. The result is a simple, inexpensive structure that blends in with almost any environment and requires little or no heat from any source except the sun.

1kitap1.com/en Heat-Conserving Characteristics A typical conventional greenhouse is eight feet high and of glass-to- ground construction. This means the glazing material, whatever it may be, extends to just a few inches above the ground. This design provides some light for growing plants under the bench, but it also lets out a significant amount of heat. Heat is lost through the glazing or through tiny cracks between panes of glazing, or through joints in other parts of the structure.

In colder climates, greenhouses frequently are built on three-foot sidewalls of concrete block. This decreases heat loss, but is not nearly as energy-efficient as the pit design. The most distinctive characteristic of the solar pit is that the walls of the greenhouse are underground. They are constructed to ground level of concrete and two inches of foam insulation; sometimes they are simply concrete piers with foam insulation lining the perimeter from below the frost line to ground level.

There are two heat-conserving benefits to this system. First, the walls are in contact with the earth. Since the earth below the frost line remains a pretty consistent 50°F year round, the walls are significantly warmer than the outside air in winter. In addition, the pit design means the walls are protected from the cooling effects of high winds. Heavily Insulated Not only is heat loss through the walls cut to just about zero, but also the solar pit is heavily insulated.

From a heat standpoint, the traditional greenhouse is a big loser because it is walled and roofed entirely in glass, or some other transparent material, with a minimum of framework to block the light. For example, if you are trying to maintain a temperature differential of fifty degrees between the greenhouse and the outside, it takes eighteen times as much heat in an all-glass structure as in a structure entirely insulated with four inches of fiberglass.

If you use a double layer of glass — a good conservation measures — heat loss can be reduced as much as 40 percent. At best, however, you are still losing about ten times as much heat through the glass as through an insulated wall. In the solar pit greenhouse, the pit sides, north-facing wall, and north roof are heavily insulated.

This is a short excerpt from the opening of “” by Unknown, quoted for review and introduction purposes. All rights belong to the copyright holders.

Book Information

• Unique ID: d8ba5fe0a7efa0cb
• File Extension: .pdf
• File Size: 6,362,478 bytes (6.068 MB)
• Title: –
• Author: Unknown
• ISBN: 0882662112
• Pages: 43
• Language: English (en)

Reading & Word Statistics

• Estimated Reading Time: 44.31 minutes
• Total Words: 8,863
• Total Characters: 51,857
• Average Words per Page: 206.12
• Average Characters per Page: 1205.98

Most Frequent Words

greenhouse (105), heat (69), pit (64), use (35), north (35), roof (32), used (30), wall (29), solar (28), light (28), between (26), fiberglass (26), also (25), feet (24), plants (24), good (24), design (22), walls (22), even (22), air (21), make (21), foundation (20), glazing (20), storage (19), space (19), water (19), one (19), greenhouses (18), glass (18), kitap (17), two (17), insulated (17), com (16), winter (16), day (16), shutters (16), polyethylene (16), get (15), however (15), growing (14), material (14), inches (14), system (14), much (14), small (14), inch (14), many (13), concrete (13), loss (13), insulation (13), temperatures (13), soil (13), night (12), keep (12), want (12), outside (11), wide (11), crops (11), place (11), work (11), need (11), building (10), size (10), look (10), sun (10), frost (10), line (10), south (10), three (10), either (10), low (10), attached (10), don’t (10), far (10), freezing (10), problems (10), available (9), materials (9), structure (9), construction (9), means (9), best (9), large (9), inside (9), although (9), profile (9), build (9), find (9), well (9), special (9), way (9), you’ll (9), long (9), sure (9), relatively (9), wood (9), panels (9), high (8), energy (8), take (8).

PDF Download