Case Studies

Please find below a selection of case studies across industry sectors, data sheets and other useful information for your convenience (links download a pdf file).

Case Study: Nottinghamshire Police Headquarters

Work Carried out by: Carbon Zero Consulting Ltd
Application: Assessment of viable renewable technologies to replace 1.5MW of oil boilers.
Completion Date: January 2016
Project History
Sherwood Lodge is the headquarters of the Nottinghamshire police constabulary sited within a large wooded campus to the north of the city. Carbon Zero Consulting were contracted to assess viable technologies to save the constabulary money on their heating – and to reduce their carbon emissions.

We carried out a detailed heat-loss assessment of the various buildings to determine whether the existing 1.5MW oil boilers were correctly sized. The heat loss model suggested the boilers were ‘generously sized’ to provide at least 50% over-capacity.

A renewable heating technology sized to provide 500kW would provide over 90% of the required heat input to the various large buildings.

Project Description
A review of underlying geology and hydrogeology concluded that the site was an excellent candidate for a ground source heat pump (GSHP) solution. However, further analysis of the heating emitter systems in the various 1960s and 1970s office blocks showed that a 50°C heating system (using heat pumps) would not be suitable.

As such it was concluded that the best technology to reduce carbon, reduce costs and attract income from the renewable heat incentive (RHI) would be biomass.

Carbon Zero Consulting were asked to develop specifications and drawings and to manage a tender process to identify a suitable contractor to complete detailed design and install a suitable system consisting of 2 containerised boiler rooms with integral wood pellet stores.

Outcome
The tender process identified Ashwell as the preferred supplier. Carbon Zero Consulting worked alongside the estates department of Nottinghamshire police during the installation period and for the RHI application process.

Two large containerised biomass plant rooms have been installed to provide a total of 520kW of heating from wood pellet. The two systems were commissioned in late 2015 and early 2016. Both systems comply with RHI regulations.

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Case Study: Wilkinsons (Wilko) Supermarkets

Work Carried out by: Carbon Zero Consulting Ltd
Application: Renewable technology evaluation and Open Loop GSHC trials.
Completion Date: June 2015
Project History
The board of Wilkinson Supermarkets (Wilko) takes a very long term and sustainable view of energy use – especially for their head office buildings near Worksop.

In 2012, Carbon Zero Consulting (CZC) was asked to carry out technical, geological and financial assessments of the most suitable (renewable) technologies to replace their current LPG gas boilers (and split system chillers). This detailed assessment identified the underlying geology as being very well suited to the use of open loop ground source heating and cooling (GSHC).

Further feasibility assessments were carried out by CZC in 2014 including detailed heat loss modelling and specification of mechanical and electrical (M&E) modifications that would be required to enable a low temperature, high efficiency GSHC system to provide heat and cool for various scenarios of head office accommodation. This was followed up by drilling the first of potentially 2 or 3 open loop boreholes on the head office site to confirm the presence of the predicted geology and to test for the available flow rate of groundwater – and the quality of that groundwater.

Project Description
Drilling and testing was performed in 2014 with excellent results. It is expected for the full scale project to go ahead once plans for the Wilko head office refurbishment are finalised later in 2015.

The final scheme will be designed to comprise 2 or 3 open loop boreholes, each with pumps installed to allow an ‘ATES’ system to operate. An ATES system allows greater efficiency of heating and cooling by building-up a resource of warmed or cooled groundwater adjacent to each borehole. The building management system (BMS) will demand water from the resource warm or cool borehole depending on the building’s requirement at that time.

Case Study: Soil Surveys

Work Carried out by: Carbon Zero Consulting Ltd
Application: Soil thermal conductivity testing.
Completion Date: Ongoing since 2012
Project History
Ground source heating and cooling (GSHC) has become a widespread technology for the provision of renewable heating throughout the UK. GSHC technology is the most efficient method to provide renewable heat, provided the building is suited to provision of low temperature heat AND the ground array is correctly designed and installed.

There are several methods for ‘harvesting’ renewable heat from the ground as part of a GSHC system. The most widespread method, for domestic and smaller commercial applications is to use a shallow, horizontal collector consisting of pipe, or ‘slinky’ pipe within trenches excavated into the soil (to a depth of about 1.2 – 1.5m).

A designer and/or installer of such a system needs good knowledge of the soil temperature and soil thermal properties (as well as the heating requirements of the building) in order to construct an efficient and long-lived shallow ground array. If there is insufficient area of land, or too little pipe, then the heat pump will reduce the temperature of the soil to a point where the system operates very poorly or freezes entirely.

Project Description
There are no soil maps available to gauge the thermal conductivity (λ) of a soil at a particular location. BGS sell λ data for underlying bedrock, but there is currently no free-to-use or other source of data for soil properties. Furthermore; soil properties are highly variable over short distances.

To ensure the ground array is correctly sized for the duty required by the heat pump, Carbon Zero Consulting offers a unique service to measure the thermal conductivity of the soil in-situ, at the precise depth that the ground array is to be installed. We have provided surveys and data analysis for over 50 sites throughout the UK for domestic applications and commercial systems of over 200kW.

Our site-averaged soil thermal conductivity (λ) data is used by designers and installers to calculate or model the extent of the ground array. The measured, site-specific, data is used as an input parameter within design software, or within the MCS ‘Ground Heat Exchanger Look-up Tables’.

Use of the Tables is made very straightforward with our survey data as the 2 input parameters required are clearly presented within our reports for direct Table input – in fact we do this for you!

We have many examples where our measured value of λ is significantly at odds with the ‘assumed’ or estimated values intended to be used by an installer prior to our survey. This has saved the installer the expense of installing too much pipe, or more importantly saved the potentially huge expense of under-designing a ground array – with all the potential problems that can cause with poor system performance.

Case Study: Calypso Soft Drinks (now part of Cott Group)

Work Carried out by: Carbon Zero Consulting Ltd
Application: 3 boreholes supplying the only source of Spring Water.
Completion Date: Ongoing
Project Description
Calypso Soft Drinks produce a range of soft drinks from their large production facility in Wrexham, North Wales.
The factory is supplied with water from 3 boreholes drilled in the 1990s. The boreholes take high quality groundwater from the sandstone formations at a depth of 100m below ground. This groundwater resource is vital as it provides the only source of Spring Water for their wide range of soft drinks. Naturally, the boreholes are very closely managed and monitored. Carbon Zero Consulting, with local borehole contractor Wyatts, has been providing expertise to help Calypso manage their groundwater resources for many years.

Case Study: ASDA Stores Ltd in Bootle, Liverpool

Work Carried out by: Carbon Zero Consulting (CZC) on behalf of Cool Planet (now part of Econergy).
Application: Open Loop Ground Source Cooling
Date: January 2008
Project History
ASDA’s Bootle Superstore (3700 m2) set new standards in how to develop modern, low carbon and energy efficient stores. The store design was industry–leading in its use of a combined biomass boiler, ground source cooling and CO2 refrigerant heat reclaim to produce hot water. As part of its firm commitments to reduce carbon emissions and improve energy efficiency in a sustainable way, ASDA commissioned Cool Planet and CZC to design and install the ground source elements of the low-carbon store.
Project Description
The first stage examined the viability of using ground source technology to provide an open loop groundwater cooling solution capable of delivering 740kw of cooling at peak load. Underlying geology, site layout, groundwater quality and many other factors were assessed and modelled to develop borehole designs.
CZC obtained all the necessary regulatory consents to allow drilling and testing of the system. An open loop array comprising 2 boreholes, pump and re-injection pipework were designed and installed. CZC went on to complete all remaining regulatory steps to obtain an abstraction licence and discharge permit – including thermogeological modelling of the thermal plume of groundwater created by the constant cooling load.
Outcome
• The store is over 40% more efficient, and emits up to 50% less CO2, than an equivalent Asda store built in 2005.
• The yield from the aquifer is delivering the required yield
• The building has been running very efficiently since its installation in 2008.
Awards
As one of their most environmentally friendly stores to date, they were delighted when it was awarded ‘Excellent’ on the BREEAM rating and ‘Exemplar’ by the Carbon Trust.

Case Study: St. John Fisher Catholic Primary School, Perivale (Archdiocese of Westminster)

Work Carried out by: Carbon Zero Consulting Ltd, on behalf of Cool Planet (now Econergy).
Application: Open Loop Ground Source Heat Pump via 2 boreholes.
Completion Date: December 2008
Project history
After many years of enduring accommodation in very poor condition and across a split site, separated by London’s busy A40 trunk road, the Diocese of Westminster secured funding to enable redevelopment – to include renewable heat and power technologies. Carbon Zero Consulting reviewed geological, hydrogeological and thermogeological conditions to assess whether, and what type, of ground source heat pump (GSHP) system might be suitable. It was concluded that the underlying geology was suited to an open loop system. Infant pupils were temporarily relocated and their site completely redeveloped to provide a brand new 446-pupil primary school. The doors to this new low carbon school opened to excited pupils and staff in January 2009.
Project Description
Following detailed assessment of the underlying hydrogeology, CZC provided borehole designs for a ground source heating system to take water from the underlying chalk aquifer. Prior to mobilising drilling equipment, we provided the regulatory input to obtain drilling and test pumping consents from the Environment Agency. CZC went on to supervise the drilling, construction and testing of the 2 boreholes. An open loop system comprising two boreholes was installed. Groundwater pumped from one borehole at a temperature of 11°C, passes through heat exchangers connected to heat pumps and returns to the chalk aquifer via the second borehole at a lower temperature.
Outcome
This Ground source heat pump system was installed prior to the RHI scheme. It has operated continuously and efficiently since 2008 – and provides all the school’s heating at a much lower cost than oil or LPG – and without the requirement for fuel delivery. This technology, together with automated passive ventilation, provides a high level of renewable energy generation on site.

Thermal Response Testing (TRT)

An example of a Thermal Response Testing report.

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Case study, Social Housing & Ground Source Heat

28 Houses and 6 apartments were refurbished including replacement of oil boilers in this ground source heating project for social housing in Wales.

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Example Georeport

An example closed loop design report for domestic or small commercial applications.

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CZC Water Management

A selection of some of our Water Management services.

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CZC Energy Management & Renewable Energy

A summary of some of our services in Energy management & Renewable Energy design.

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