Field servicesCarbon Zero Consulting provide a full range of Field Services for Ground Source Heating & Cooling projects as well as supervision of drilling and testing boreholes for water supply, contaminated land and environmental monitoring;
- In-situ measurement of soil thermal conductivity/resistivity utilizing the Hukseflux FTN01 rugged thermal needle instrument (we are the only providers of this service in the UK).
- Closed loop borehole thermal response testing (TRT). We utilize a number of testing systems for piles and boreholes of depths of 10m up to ≈400m
- Supervision of borehole drilling from domestic scale to largest commercial water supplies for GSHC and water supply projects
- Design and supervision of test-pumping programs for GSHC and water supply projects
- Water sampling and analysis of chemical & microbiological results for groundwater supplies
- Stream and river flow measurement utilizing impeller flowmeter
- Installation of borehole, spring and river monitoring equipment for physical and chemical parameters
- Field assessment of water and wastewater treatment systems including sampling and analysis of effluent and treated waters
- Supervision and interpretation of all geophysical and CCTV surveys
- Installation of transducers and data loggers into boreholes for collection of data for test pumping of boreholes. We own an array of borehole pressure/temperature transducers and data loggers and borehole ‘dip’ tapes.
Ground Water ServicesCarbon Zero Consulting provide a full range of Field Services for the exploration, development, management and treatment of process water and groundwater.
Thermal Response TestingCarbon Zero Consulting operates several specially packaged, thermal response test (TRT) systems for testing of closed loop borehole and piles of any depth between 20m and up to 400m. We have provided well over 100 successful tests in boreholes from Cornwall to Orkney.
A TRT provides in-situ measurement of site specific thermal properties of the ground into which a closed loop system is being installed. The measured values derived from a TRT are used to calibrate a design model and confirm the design, number, depth and spacing of boreholes required to meet your building heating/cooling requirements.
Testing might be completed in a pilot borehole prior to project commencement, or whilst the array boreholes are being drilled. In the latter case we are able to quickly update desk study design calculations and confirm total numbers of boreholes.
Good TRT practice requires accurate measurement and logging of flow and temperature to and from the test borehole. A reliable and consistent source of power (heat) must be available. We provide a suitable generator and fuel supply to allow thermal testing for up to 72 hours.
Interpretation of the thermal response test is as important as acquiring good data. An experienced eye is required to identify when and where data is valid. We always aim to process and interpret the test data within 24 hours of test completion to provide our client with a reliable, measured values for background borehole temperature, apparent borehole thermal conductivity and borehole resistance.
Example project: Mobilise a TRT system to 2 sites on the Isles of Orkney to test one existing borehole and a newly drilled borehole as part of GSHP systems to provide low-carbon heating for sheltered accommodation for the elderly.
Soil Thermal Conductivity Testing
We are the UK’s only providers of this service and have performed over 200 surveys throughout the UK. For the GSHP sector and power cable installation contractors.
For shallow horizontal GSHP systems, this is of vital importance as this measures, directly, the thermal conductivity of the soil at the location and depth of the proposed heat-exchange pipework array.
During a typical test, a small electrical voltage is applied to a resistance element in the probe. This results in a constant heat power being generated, which propagates radially into the surrounding soil. The temperature of the probe increases with time and this increase is monitored over a heating cycle of around 5 minutes. If radial heat conduction is assumed, the temperature should increase in proportion to the logarithm of time, according to a standard “line source” approximation.
Analysis of the rate of temperature increase provides a value of the surrounding soil thermal conductivity (or resistivity).
A representative assessment of a site’s “bulk” soil conductivity (i.e. a single value that can be used in design software) requires a number of individual determinations distributed across a site; usually between 12 and 25 measurements depending on the size of the scheme.
A survey to obtain sufficient samples for a typical domestic GSHP application requires 1-day surveying in the field plus time for data analysis and reporting.
Call or email us to find out more.
We utilise a ‘Hukseflux FTN01’ Field Thermal Needle Probe System (see image on right). The probe itself comprises a thermal needle of diameter 6.3 mm and 170 mm length, mounted on a 1.5m long handle. This allows for in-situ measurement of thermal conductivity or resistivity in undisturbed soil.