Additional resources that support our products.
Yes, if we assume that the following clauses are met:
4.3.1 Permitted as alternative methodology;
4.2.12 " Validated for UK use..." due to use of UK climate files;
4.2.12 a) Site average ground temperature is an input and hourly air temperatures form part of the hourly climate data;
4.2.12 b) Site ground thermal conductivity value (in W/mK) is an input and the user can consider the depth of the water table;
4.2.12 c) The annual heating energy consumption for space heating & domestic hot water are input/calculated values;
4.2.12 d) The power extracted from the ground (in kW) is stated;
4.2.12 e) The temperature of the thermal transfer fluid entering the heat pump is stated graphically throughout the year;
4.2.13 The temperature of the thermal transfer fluid entering the heat pump can be designed to be >0oC at all times using a 20-year average climate file since the temperature is specifically shown graphically in the results.
With these assumptions, a GeoT*SOL quote can be used as an "alternative methodology" and should be used in conjunction with the MIS 3005 methodology-based quote.
The basic message is that the MIS methodology has a very limited number of variables that it considers, whereas GeoT*SOL basic is for design and anticipates a wide range of variables. For more details about the SAP methodology and Valentin software see: here.Back to top
The "Primary energy savings" & "CO2 emissions avoided" figures listed in the project report are comparing the energy running costs of your designed heat pump system to a natural gas heating system.Back to top
The problem of cooling the ground can be resolved by undertaking one or more of the following design actions:
Reduce space heating or DHW heating demand.
Increase total length of borehole heat exchanger (either number or depth of boreholes).
Changing the grouting type from "simple grouting" to "thermally enhanced infill".
Changing the diameter of the borehole.
Increasing the size of electrical element specified.
Altering the "double u pipe" or "single u pipe" parameter.
Altering the capacity of the selected heat pump.
Please note: The effects of changes to the design (on the warning message) will only be taken into account when you run another simulation.Back to top
The specific extraction rate represents the limit of the rate of heat extraction from a borehole. It is a value that has critical affect on the success of a borehole heat pump system. The extraction rate values are best derived from scientific experiments on each geological type that surrounds the borehole and these are often held in commercial confidence by experienced bore-hole operators. As a starting point, typical data leading to identifying values can often be found from professional organisations. For example in the UK, there is the British Geological Society (BGS) who keep record of borehole scans on their website, which can be used to identify ground conditions. Other sources include:
Consultant geologist or hydrogeologist
Recorded observations from test pits
Experience from a nearby site and confirmation of consistent geology in the area.
Further guidance is also available from the UK's Microgeneration Certification Scheme especially their documents MIS 3005 – 'Supplementary Information' and MCS 022 'Ground Heat Exchanger Look-up tables'. To find the correct table within the latter document, you would need to calculate the FLEQ run hours as follows: FLEQ = Total energy consumption (kWh) / Heat pump capacity (kW).
For more thermal conductivity values, also see Appendix C ' Values for thermal conductivity' in MIS 3005. Please note the assumptions for each table are listed above each table which can be inputted into GeoT*SOL basic as in the following example or adjusted for each project accordingly:
Borehole diameter = 130 mm
Construction type = Single U-Pipe
Infill = Thermally enhanced.Back to top