Inside the Proposed Energy Apron : Image : Davide Mazzaglia

The main feature of the Energy Apron is the incline of the topography. The membrane that produces the greenhouse effect is thus covering a series of large terraces on which this main layout are also developed:

1. Three receptacle-retainers producing the step-down topography;
2. The “tree columns” supporting the membrane structure;
3. The taut membrane and its stretching jacks.

The incline of the whole system has two main effects:
A temperature differential between the terraces with the lower terrace as the cooler, the top as the warmer.
An updraft of air warming up as it moves from the bottom toward the top (Chimney Effect).

The Receptacle Retainers:

1. A retaining structure stabilizing the ground and defining the terraces.
2. A definer of a space that is sheltered from the direct azimuth radiation -- those that in the winter night kill all vegetation that is not frost-resistant.
3. An enlargement of the cultivation area under greenhouse conditions.
4. A heat sink because of its mass of concrete causing therefore a milder climate in the night chill. With the addition of a curved screen and a vertical curtain, the receptacles can be called a ‘greenhouse-within-a-greenhouse.’

Tree Columns : Image : Davide Mazzaglia

The “Tree Columns”
The four steel columns composing each support of the steel pipes forming the membrane anchorage are defining space (2m X 2m) where cylindrical and openable containers are positioned. A tree can be planted in each container. The trunk of the tree protrudes outside of the membrane surface and the (deciduous) foliage shades, during the warm-hot season, a high percentage of the membrane.

The design makes possible the following:

1. A double-tiered cultivation. For example: vegetables inside the apron and grapes on top of the membrane.
2. An improvement of climate during the summer months inside the apron caused by the shading of the foliage.
3. An access to the root system of the planted tree because the root system can be washed clean, investigated and put under diverse environmental situations - temperature, humidity, nutrients, symbiosis, etc. Each column could thus be a small laboratory working at the tree’s “metabolism.”

The Taut Membrane
Reasons for the adoption of a plastic membrane instead of a glazed diaphragm:

1. Cost: The cost of the membrane is a fraction of the cost of a glass diaphragm.
2. Maintenance: The necessity of replacing the membrane every three to five years is compensated by its pristine aspect as compared against the dirt, dusty, littered glazing and its paneling.
3. Flexibility: It is relatively easy to take off or put on the membrane if and when the climate suggests the desirability of doing so.
4. Design Characteristics: The membrane is taut by the opposite action of the peripheral anchorages and the inside jack pressure. The result is an elegant float-like diaphragm with its own specific tensile geometry.
5. Industry Availability: Industry is producing plastic cloths with diverse characteristics capable of taking the best advantage of sun and temperature conditions.

At bottom, the Energy Apron wants to be more than an optimal greenhouse. As the term suggests, it is like an ‘apron of energy’ draped around the habitat to which it can deliver energy in three forms:

1. Green food
2. Hot water
3. Warm air

In this first design only the upper terrace has room for hot-water solar collectors. But in addition, the Apron likes to be seen as an elegant, efficient, inviting space where, for instance, the process of vegetable growth might be carried beyond into the steps of preparation and of consumption. Therefore, in one area in the Energy Apron, tables, chairs and parasols will be arranged for simple meals where the customer, depending on the season, might be able to choose the greenery for his own salad -- to be consumed on the spot or to carry away.
On the environmental - energy level, the proximity of the habitat to the energy source (food, hot water, warm air) goes quite a way to generate that “affordable future” we so desperately need. The better-controlled water use facilitated by the Energy Apron is also paramount in arid climates. When feasible, areas of the Energy Apron can be “leased” to individuals for their garden patch.