Seasonal energy storage

A marriage between solar energy and the thermal constancy of the ground offers an opportunity to make significant reductions in both the heating and cooling loads generated by buildings. Known as 'aquifer storage' the principle is that, in summer, buildings absorb considerable amounts of surplus heat which can either be vented to the atmosphere or used to provide a reservoir of warmth for the winter. The energy storage system comprises two wells drilled into the water table below the building, one warm the other cold. The system relies on the fact that ground water is a constant (10-12°C in the UK).

This system should be distinguished from the tanked seasonal storage at Frierichshafen described earlier which is fed by solar thermal panels.

In summer water from the cold well is pumped into the building and, via a heat exchanger, cools the ventilation system. As it passes through the building it absorbs heat ending up at around 15-20°C. It is then Figure 13.7 returned to the warm well. In winter the system is reversed and warm

Principles of seasonal storage water heats the ventilation air. It loses heat to the building and returns to

(courtesy of CADDET) the cold well at about 8°C to be stored for summer cooling (Figure 13.7).

Winter

Basic functioning of energy storage in aquifers.

Heat Exchanger

Cold circuit

Cold well .

Cold circuit

< -

<

Aquifer 10°C

Winter

Natural Ventilation Reichstag Building

Summer

The Netherlands are leading the way in this technology with 19 projects completed or under way with a projected annual primary energy saving of 1.5 million cubic metres of natural gas equivalent. Recent buildings to benefit from this technology include the Reichstag in Berlin and the city hall and Schiphol Airport offices in The Hague.

In the case of the Reichstag surplus heat is stored interseasonally in a natural aquifer 400 m below ground. Aquifers at 40 m depth are used for cooling.

The Sainsbury supermarket at Greenwhich Peninsular, completed in September 1999, employs earth sheltered walls to regulate temperature on the sales floor. Ventilation air is passed through underground ducts to maintain cooling. Also there are two 75 m deep boreholes, one absorbing heat from refrigeration equipment, the other providing ground cooling.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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