Integrated Systems

Energy Management

Integrated Combined Energy Management

Our energy is generated on site with the highest efficiency and conservation, and stored electrically and thermally to be used year round. Efficiency is further managed and enhanced with a plant room hidden between each pair of lodges, that allows easy and visual connection of all systems, ensuring high integration, quality maintenance and upgrade capability is built in, while obsolescence is designed out.

Electrical Demand

This is difficult to accurately predict as we will have variable occupancy in the four lodges and the variety of guests will use facilities in different ways. We will use efficient lighting and appliances to minimise consumption and variation, but we expect hot water to be a much higher demand, and this has driven the large amount of thermal storage.

Heating, Cooling & Ventilation

Space heating requirement in the lodges will be minimal, if any, due to the insulated high thermal mass, solar gain and residual heat from occupancy. However a radiant heating/cooling loop will be installed in the floor just in case it is needed on occasion, for heating or cooling. On sunny days our solar PV will be running heat pumps to charge the thermal store, allowing free cooling capacity at the same time. Natural ventilation will also be built in, plus heat recovery via the exhaust heat recovery in the MVHR unit in the roof space. This will use a heat exchanger to the GSHP, and be able to harvest internal heat and warm air from the solar chimney built into the roof fabric. Of course the front, side and rear glass doors can be opened to bring the outside in at any time.

Solar Gain

The lodges are positioned in a gentle arc facing south, and all feature a sun terrace with an insulated roof and large rooflights (with blinds). This provides user variable shading in the summer and maximum daylight in the winter. The high thermal mass floor can absorb any warmth from the sun during the day and release it in the evening. Excess heat can be harvested by the heat pump and dumped in the thermal store, ensuring a comfortable environment at all times.

Solar Thermal

The sun terrace roof has prime exposure to the sun and will include integrated solar thermal loops that can directly harvest heat to the thermal store, or indirectly via the heat pump. We will also integrate solar thermal collection within the parapet roof, with the additional bonus of cooling the rear of the solar PV panels to increase their efficiency.

Solar PV

Up to 55 PV panels can fit within each lodge roof, 29 are South facing and the rest are shallow North facing so only 70% efficient. A further 68 panels may be placed on the barn roof, in total up to 288 panels giving 72kW and providing up to 65,000kWh per year. The challenge is surviving off-grid through the winter where output is dramatically reduced, hence the large number of panels. Winter sun is often diffused and reflected so without much direct sun the difference between North and South facing output is less marked.

Heat Pumps

A ground source heat pump (GSHP) for each lodge is positioned in the plant rooms, supplemented by an additional thermal harvesting within the parapet roof to harvest ambient air temperature. A small air source heat exchanger may be positioned in the plant room to harvest a flexible hot air dumping zone. In combination when there is any spare solar power they will work to harvest every available source of heat within the lodges and service tunnel and store it in the thermal stores.

Masonry Stove

A double sided cast iron multi-fuel stove will be built into the rammed earth hearth in the living area. The system will promote secondary combustion and masonry heating. A closed loop water boiler is incorporated for DHW.

Electrical Storage

A bank of electrical storage batteries is positioned in the service tunnel. Flow batteries are a new technology that seems particularly applicable, and will be investigated.

Thermal Storage

Huge underground thermal energy storage (TES) is positioned under the front garden of each lodge. With the ambient ground temperature around 10°C we hope to drive the TES core up to 50°C by autumn so that energy can be used in the depths of winter to deliver hot water via the heat pumps. In addition each lodge has a large thermal store tank kept to around 60°C that will heat DHW as it is drawn, so there is no separate DHW cylinder.

Idyll Energy Challenge

We have devised an integrated energy system for the site that allows us to be off-grid all year round. We challenge the wider informed community to review, analyse and put forward ideas to ensure the entire system is as good and efficient as it can be.

Water Management

Water

All our water is harvested on site from rainwater and borehole, it is used and reused. Greywater is processed on site, cleaned and safely used for irrigation and the toilets. Blackwater will go the the mains sewerage as the most environmental method available. The picture shows the current borehole system that will be substantially upgraded.

Waste

Greywater will be collected separately from baths and showers and treatment will be processed by a small reed bed for use in toilets and for irrigation. Waste water heat is recovered by piping it through a wet sand box with the heat pump thermal exchange loop, ultimately transferring heat to the thermal storage.