Geothermal Storage

PVT (PhotoVoltaic Thermal) Boreholes are a little different to normal Geothermal Boreholes in that they are used to pump heat into the ground for storage, as well as extracting it. This is another way to achieve Carbon Footprint Reduction.

The principle difference lies in the nature and material of the loop inserted into the borehole. (more information)

The material of the PVT loop must be able to withstand the much higher temperatures of the coolant return from the solar hybrid roof panels, (up to 95 Deg. C), than those required for Ground Source Heat Pump operation.

Synergy Boreholes and Systems Ltd. will be cooperating with a leading renewable energy systems installer, Paynes Energy Solutions to offer the latest, more effective PVT technology in the South of England

What is PVT?

PVT, PhotoVoltaic Thermal

A PV-T collector is a combined assembly of a PV module - for the conversion of electrical energy and a high efficiency flat plate solar collector - for the conversion of thermal energy.

A PVT module produces 43% more primary energy than a conventional solar thermal collector per unit surface area, and even 96% more than a conventional PV module. In addition, the integration of the two technologies leads to large potential savings in material use and in production, balance-of-system and installation costs. This also gives PVT an aesthetic advantage: only one building element is required to produce both forms of solar energy, leading to a more homogeneous roof or façade appearance.

Photovoltaics (PV) are semiconductors, as such they have one drawback. Substantial degradation in performance at increased temperatures.

In the UK, on a sunny summer’s day in mid summer, when you hope to make the most of your PV, array, panel temperatures can reach over 100ºC. At this temperature the system will produce less than 10% of its maximum output, rendering it largely useless for a much of the day.

By regulating panel temperature using fluid cooling, an optimized system can be produced, balancing PV efficiency and thermal output. It is thus possible to obtain a higher electrical yield - up to a 40% increase compared with the equivalent area of mono-crystalline PV and enough free heat to offset the annual heating requirements of the average house.

PVT collectors allow you to construct a “total solar energy system”, for both electric and thermal energy generation. Also, because of its cooling-effect on the PV module, this system has a higher efficiency at a much lower cost price than separate systems. In combination with geothermal storage, this can be used to take low energy buildings to, or near to, zero-carbon emission. (see also Carbon Footprint Reduction)

The heat obtained from PVT panels during summer months is stored deep in the ground where it can be extracted during winter months when there’s not enough solar energy to adequately provide heat to a building. In order to do this, a heat pump and boreholes of 100m depth or more are required. Geothermal heat storage allows storage of thermal energy for more than a year. 

Geothermal Boreholes

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