Which Geothermal System Should You Choose?
There are two types of geothermal ground coupling techniques (Open Loop and Closed Loop). Open Loop techniques can include abstraction and re-injection wells and river or ocean Heat Exchangers. There are several variations of Closed Loop Systems and techniques including vertically drilled boreholes, horizontally laid pipes, energy piles and pond or lake loops. All reasonably sized Schemes should have a Feasibility Report carried out at an early stage (Stages A-B) LoopMaster will determine the most cost effective Ground Coupled System to meet the Employers requirements. It may be a Hybrid System of more than one technique. If the team has already chosen a preferred technique, LoopMaster will demonstrate to the team how it will work and what carbon reduction can be realised.
The best way to proceed is for you to contact our team of experts to discuss your requirements.
Open Loop Systems
An Open Loop System involves pumping water from an existing source, perhaps a river or a lake, but more often via boreholes that are drilled to access water sources below ground for efficiency.
The water either travels directly to the integral Heat Pump or more commonly via a Plate Heat Exchanger.
All Open Loop Systems using over 20m³ of groundwater per day are subject to lengthy and complex Environmental Agency (EA) Regulations. The EA are reasonably relaxed about Open Loop Groundwater Systems if spent water is returned to the aquifer from which it was taken, meaning that net permanent consumption is relatively small. It must be demonstrated to the EA that the System is not going to affect an existing user of groundwater in the vicinity of the Project and that it offers no potential threat to the environment. LoopMaster Designers, Project Managers, Hydrogeologists, Groundwater Modellers and Supervising Engineers work very closely with EA officers to ensure that the Scheme will operate within EA guidelines and just as importantly, we will demonstrate the sustainability of the System.
If you would like to discuss Open Loop Systems please contact us now.
Closed Loop Systems
Closed Loop Systems utilise, as the name suggests, a system of plastic pipes which simply circulates fluid (water and environmentally friendly anti-freeze) through the ground absorbing heat (heating) or rejecting heat (cooling). The Heat Pump either increases the temperature for heating or decreases it for cooling, dependant upon the needs of the building.
In a currently unregulated industry in the UK (unlike the USA), there are unqualified people from all walks of life designing and installing fairly sizeable Closed Loop Systems. Closed Loop Systems need to be designed by people trained and qualified to do so. There are so many Schemes being installed based on ‘rule of thumb’ criteria that can be massively misleading. A common assumption is the dreaded 5kW from a 100m deep borehole and borehole centres of 5-6m apart. In reality, borehole depths generally range from 40m to 200m and the ‘output’ or ‘input’ capacity of a borehole could vary by a factor of ten. Whilst it is acceptable to use generalised estimations for initial concept work, this should be left behind once at Stage B and this is where a Company such as LoopMaster should drive the project forward in an informed way.
If you would like to discuss Closed Loop Systems please contact us now.
Even a badly designed Closed Loop System may work initially! It may take many months or even years for the ground loop to overheat or freeze. The System may continue to work, however, it will be inefficient and unsustainable and any carbon reduction targets would be missed. At worst, the System could fail altogether.
In simplistic terms, think of it like the following analogy.
Imagine the ground is a rechargeable battery always on ‘trickle’ charge from the geothermal decay (heat source). If you are taking energy out (heating) at a greater rate than the ‘battery’ is being charged, it will go flat, or in this case the ground temperature will drop to unacceptably low temperatures. The System would therefore be unsustainable.
The reverse is also true.
If you are rejecting heat (cooling) to the ground at a rate that is greater than can be accepted, you are effectively over-charging the ‘battery’. In this instance, the ground temperature would become too high, again, making the System unsustainable. This can be overcome by using a qualified and skilled Loopfield Designer to size the ‘battery’ to ensure it is sufficient to sustain your System. Getting the loopfield designed correctly is also more likely to save the team money. A specialised Loopfield Designer can accurately determine the required amount of loop in the ground cutting out unnecessary, expensive drilling (a common occurrence). Uncertainty can lead to over-design and boreholes can be expensive.
It is these calculations and attention to detail that make LoopMaster industry leaders in Geothermal or Ground Source Systems.
To avoid the cost of getting it wrong call LoopMaster (Europe) Ltd now and we'll be happy to discuss your Project with you.