Читать книгу The Self-Sufficiency Handbook - Alan Bridgewater - Страница 62

If you have a conservatory, you will know how quickly it heats up. Conservatories are wonderful places to be in late autumn and early spring. Even on a relatively cold autumn or spring day, they feel comfortable. Yet, in late spring through summer and early autumn, when the sun is beating down, they are usually far too hot. For the most part, when the conservatory is too hot, say in early autumn and late spring, the house can be a bit chilly.

At this point, what most of us do without really giving it much thought is open the doors that link the house to the conservatory so that the heat flows into the house. You could take this basic approach one step further and build vents in the linking wall at floor and ceiling levels—much like the Trombe wall—to create a chimney effect that draws hot air into the house. Alternatively, you could fit an extractor fan in the top vent and send hot air via ductwork to a colder part of the house. All you are doing, in essence, is taking the unwanted hot air and putting it someplace where it is wanted.

The “greenhouse rock storage” option takes this way of thinking one step further and tackles the house-too-cold/conservatory-too-hot scenario. The sun heats up the structure of the conservatory—the walls and floors—so that the air becomes hot and starts to rise. At this point, an extractor fan switches on and draws the hot air out of the conservatory and sends it, via ducts, into an insulated space full of rocks, ideally an underground storage bin. Rock is usually the first choice, simply because it is low in cost and easily obtainable, but you could use any safe, inert material that is slow to heat and equally slow to cool, such as crushed concrete, crushed glass, or granulated metal. Once the heat from the air has been absorbed by the material in the storage bin, the air is circulated back to the conservatory as cool air. During the night, the hot air from the storage bin is sent by natural convection or by fan back to the house.

The rock storage approach is certainly more mechanical than the Trombe wall system, but it is a good option if you have problems with existing structures—meaning that you already have a conservatory that is too hot and a house that is too cold. It cleverly tackles both problems.