Unlike domestic installations, were many of the soil parameters are approximated, the heat source for a commercial project must be carefully investigated and designed specifically for each project.
Nutherm offer a complete service for the design and construction of geothermal heat sources. This includes:-
- Initial Geological & Site Surveys
Prior to costly onsite tests it is often useful to carry out an initial survey of the site to determine the basic geological parameters. Using online databases and mapping, basic geological surveys and our drilling partners’ years of experience, Nutherm can roughly calculate the size of the borehole array required for your project.
It is important to note however, that in most cases, these results will be insufficient to fully design a borehole array. Nutherm recommend that a thermal response test is carried out on all commercial projects
These tests are designed to physically measure the heat transfer throughout the rock surrounding the borehole. An electric heater is used to heat the water flowing through the borehole and a data logger records the return temperature over a period of 1-3 days. From these measurements, the temperature and thermal conductivity of the rock around the borehole can be calculated and hence, how much energy will be available from the borehole per year. Nutherm recommend that a thermal response test is carried out on every commercial project.
- Ground water quantity and quality testing
Groundwater provides an excellent heat source for Geothermal heating and COPs of > 5 are possible with a well designed system. For groundwater to provide a suitable source, it must be
- Within several metres of ground level to reduce pumping costs
- Of suitable quantities
- Of suitable quality
- Have a completed environmental impact study
If there is a possibility of using groundwater as a heat source, Nutherm can provide pump tests and water quality analysis. Even if the quality of the groundwater is not ideal, Waterkotte have developed a range of nickel-soldered evaporators and intermediate heat exchangers to protect the heat pump against aggressive water.
Once the physical measurements of the bedrock thermal conductivity have been taken, it is necessary to theoretically model the complete borehole array.
‘EED – Earth Energy Storage’ is a PC program designed specifically for the design of borehole arrays. Using the parameters found during the geological survey, EED calculates the influence each borehole will have on its neighbor using line model approximations and then provides recommended borehole depths, configurations and designs, based on peak heating and cooling loads in the proposed building.
It can also be used to model 2 pipe, 4 pipe and energy pile systems and can compute the results for up to 1200 individual boreholes. Using this powerful tool, Nutherm can design the correct borehole array for your project.
- Drilling by system partner
Nutherm have been installing geothermal heat pump systems in Ireland and the UK for over 10 years and have developed partnerships with several large drilling companies in various areas. Using the latest drilling technologies and techniques, we provide competitive rates for the drilling, installation of probes and grouting of closed loop borehole arrays.
- Installation - pipework, manifolds
When connecting boreholes to the plant room, PE pipe with a lifetime of over 100 years is used. All connections are carried out using electro-fusion to provide seamless, certified joints. These pipes can then be brought together at various manifolds and then into the plant room. For very large projects, Nutherm can produce custom manifolds if desired.
At various stages throughout the installation, a Nutherm representative will be available to pressure test all sections of the heat source. Nutherm will then sign off on heat source and provide all relevant documentation.