The main features that will separate an eco cave house from those of regular build are.
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1. If the property is not connected to the national electrical grid then solar energy for the generation of electricity and water heating will be utilised. This will be achieved using photovoltaic systems, batteries and inverter for power generation and thermal collectors and auxiliary equipment for hot water. |
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2. On rare occasions solar energy alone may not be sufficient to provide electricity and hot water (i.e. during short periods in the coldest and darkest winter months). As a back up it proposed to use a diesel generator, if possible, running on a bio-fuel produced in an eco-friendly manner. The generator would be water cooled, the heat from the cooling system being used to heat incoming air in the ventilation system outlined in 4 below. |
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3. In order to ensure there is always sufficient hot water it is proposed to install an enclosed wood burning stove fitted with a back boiler capable of providing the hot water requirement. These are relatively low cost, an example is a Hunter Herald 6 stove, providing up to 7kw of heat output, for more details click here |
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4. By using sealed double glazed windows and sealed doors the cave house will be virtually airtight. To preserve good air quality within the cave house it will be necessary to install a balanced ventilation system with heat recovery and air heat. These units are frequently used in passive houses of conventional construction. This system takes fresh air from the outside introducing it into the clean rooms, such as bedrooms and living rooms. Contaminated air is extracted from kitchens, bathrooms and en-suites. The outgoing and incoming air pass through a specially constructed heat exchanger so that in the winter months the outgoing air is used to heat incoming air thus reducing the amount of heating required in the cave house. In the summer months the outgoing air cools the incoming air, therefore no air conditioning is required. As a result, throughout the year, an even temperature and high quality air can be maintained throughout the house. The Indovent Temovex 400S with internal air heating radiator fits this specification. |
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5. Toilet waste will go to a pre-fabricated septic tank arrangement. The overflow will to a holding tank to be used for irrigation with the overflow from this going to a soak-away. Water from showers, kitchen etc will go to a grease separation tank and then onto the irrigation holding tank and soak-away overflow. |
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6. For external build the walls will be constructed using blocks made from inductrial hemp fibre (fibra de canamo). The walls produced from these blocks have a minimum thickness of 30 cm and extremely low levels of thermal conductivity (0.19 W/m2) providing very high levels of thermal insulation and making them suitable for passive house construction. The hemp blocks are a proven structural system ideally suited to the Andalucian climate. |  |
