What We Do
Carbon Zero Consulting applies its experience and expertise in identifying and implementing down-to-earth, pragmatic solutions.
Although our primary area of expertise is in the field of GSHC, we also have a very high level of in-house and associate expertise in the following areas:
- Air source heating
- Biomass heating and power
- Solar hot water and photovoltaic power
- Wind power
- Micro-hydroelectric
- Waste to energy
We are also very active in the provision of training and professional short courses. These include a bi-annual intensive one-day seminar on GSHC technology and ‘train the trainer’ days for heat pump suppliers and installers. We also provide all in-house training on GSHC for the Environment Agency.
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GROUND SOURCE HEATING AND COOLING
Ground source heating and cooling (GSHC) involves the recovery of low grade heat from the ground or the disposal of heat from a building into the ground, usually utilising a heat pump.
In the UK the temperature of the soil and upper few 10s of metres of rock are at a remarkably constant temperature, equal to the average annual air temperature. For example in southern England this average is about 12°C and in northern Scotland the average is about 9°C. The sun provides the majority of this heat energy with only a very small amount coming from the Earth’s interior. This why the technology is termed "Ground Source" and not Geothermal Energy!
There are two basic systems to provide a ‘ground-source’ for a GSHC system:
Closed Loop
Heat is absorbed from the ground via plastic pipes filled with a carrier fluid. The pipes can be installed horizontally in trenches, in boreholes or in a lake. The length of pipe required to provide sufficient ‘ground-source’ depends on the building’s seasonal heating/cooling characteristics and the properties of the rock.
Open Loop
In areas of suitable geology, water is pumped from a borehole to a heat pump or heat exchanger. Thermal energy is extracted from the water within the heat pump cycle. The resulting cooled water is then re-injected to the ground or disposed-of to the environment.
For both closed and open loop systems there is the option to provide cooling as well or instead of heating. GSHC systems can be designed to provide heating for a small house of say a few kilowatts (kW), up to very large commercial buildings requiring many megawatts (MW) of heat and cool.
The fundamental science behind heat transport in the ground, is directly analogous to groundwater flow. In fact commonly used groundwater analysis is based on heat flow theory. The assessment of risks associated with GSHC is therefore an extension of hydrogeology. This extension is often referred to as "Thermogeology".
Carbon Zero Consulting has specific, unrivalled expertise in thermogeology in the UK, and has been instrumental in its development, by giving specialist seminars and bespoke courses to industry and the Environment Agency.
In fact Carbon Zero Consulting are working closely with the Environment Agency to develop guidelines to aid implementation of GSHC in England and Wales. Carbon Zero Consulting’s hydrogeologists, working with specialist associates, are able to provide support to your GSHC project from concept development, risk assessment to project management, installation and regulatory permitting.
How A Heat Pump Works
Anyone who has a refrigerator or an air conditioner has witnessed the operation of a heat pump, even though the term heat pump may be unfamiliar. Space-heating heat pumps merely move heat from a low-temperature external source to a high-temperature interior space (your house).
The process of elevating low-temperature heat to 35°C or more and transferring it indoors involves a cycle of evaporation, compression, condensation and expansion. A refrigerant is used as the heat-transfer medium that circulates within the heat pump.
- The cycle starts as the cold, liquid refrigerant passes through a heat exchanger (evaporator) and absorbs heat from the low-temperature source (liquid from the ground loop). The refrigerant evaporates into a gas as heat is absorbed.
- The gaseous refrigerant then passes through a compressor where the refrigerant is pressurised, raising its temperature
- The hot gas then circulates through a second refrigerant-to-water heat exchanger where heat is removed and pumped into the building at up to 60°C, although 35 - 40°C is sufficient for underfloor heating applications.
- When it loses the heat, the refrigerant changes back to a liquid. The liquid is cooled as it passes through an expansion valve and begins the process again.
To become an air conditioner, the flow is reversed.
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AIR SOURCE HEATING
Air source heat pumps absorb heat from the outside air in order to heat buildings. There are two types of air-source heating systems. Air-to-air systems provide warm air, which is circulated within the building. Air-to-water systems heat water, which is circulated within a building through radiators or an underfloor system.
Air source heat pumps present an advantage over ground source heat pumps because they represent a lower capital cost. Instead of requiring the installation of buried underground coils, air source systems can be fitted using much less space and are therefore, more suited for an urban home and retrofitting. Compared with ground source heat pumps, however, they are typically a little less efficient in terms of running costs.
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BIOMASS HEATING AND POWER
There are various methods used to generate heat from biomass. The systems fall under the categories of direct combustion, gasification, combined heat and power (CHP), anaerobic and aerobic digestion. Before oil and gas was burned in significant quantities, biomass in the form of wood fuel provided most of humanity's heating, as well as providing our first renewable energy resource. Gas, oil and coal price increases have in turn increased awareness and value of biomass for heat generation. Forest thinnings, agricultural waste, and crops grown specifically for energy production become more competitive as the prices of fossil fuels rise.
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SOLAR & PHOTOVOLTAIC POWER
Solar PV (photovoltaic) uses energy from the sun to create electricity. PV requires only daylight, not direct sunlight to generate electricity and so can still generate some power on a cloudy day. The PV cell consists of one or two layers of a semi conducting material, usually silicon. When light shines on the cell, it creates an electric field across the layers causing electricity to flow. The greater the intensity of the light, the greater the flow of electricity. PV cells are referred to in terms of the amount of energy they generate in full sunlight, known as kilowatt peak or kWp. In the UK an installation of 1kWp will produce 800-900 kWh (kilowatt hours) of electricity per annum. For the average domestic system, costs can be around £5,000- £7,000 per kWp, with most domestic systems usually between 1.5 and 3 kWp.
Photovoltaics are increasingly incorporated into new domestic and industrial buildings as an ancillary source of electrical power. The three leading countries (Germany, Japan and the USA) represent nearly 90% of the total worldwide PV installed capacity but the popularity of this technology is growing in the UK. Most systems are linked directly to the grid. With the advent of the Feed-in Tariff (FIT) scheme starting in April 2010, producers of PV electricity will be paid for each kWh produced. For a domestic installation this payment is likely to be in excess of 30p per kWh. For larger commercial schemes it may be slightly less. Keep an eye on our Home Page as Government details are revealed!.
Solar thermal technology can provide up to 70 per cent of a house's hot water requirements. There are a number of technologies to choose from and can in many circumstances be integrated with a ground/air source heat pump system to provide all you domestic hot water needs. Feed-in Tariffs for renewable heat are being introduced in 2011 - see our Home Page.
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WIND POWER
Wind power is now the world’s fastest growing energy source and the UK has the largest wind resource in Europe. Modern wind turbines are operational for 70-85% of the time and over the course of the year, they will generate, on average, up to 35% of their theoretical maximum output. This is known as a load or capacity factor. The exact figure is dependent on the location, technology, size, turbine reliability and wind conditions. A modern turbine has a life span of 20 years or more.
We provide advice on the feasibility, design and cost for supplying wind-derived electricity to properties such as private houses, farms and offices. After identifying a good windy site, the second most important ingredient for a successful wind turbine installation is obtaining planning consent. We can provide support through this process.
The power produced by onshore wind farms is one of the cheapest forms of renewable energy available today, with the real potential for continuing technological advances to bring the costs down still further.The introduction of Feed-in Tariffs will make this technology even more attractive. Details will be posted on our Home Page as they are confirmed by the Government.
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MICRO HYDROELECTRIC
Carbon Zero Consulting can also deliver small hydro schemes. Small-scale hydropower is one of the most cost-effective and reliable energy technologies to be considered for providing renewable power generation.
In particular, the key advantages that small hydro has over wind, wave and solar power are:
- A high efficiency (70 - 90%), by far the best of all energy technologies.
- A high capacity factor (typically >50%), compared with about 10% for solar and a little over 30% for wind.
- A high level of predictability, varying with annual rainfall patterns.
- Slow rate of change; the output power varies only gradually from day to day (not from minute to minute).
- It is a long-lasting and robust technology; systems can readily be engineered to last for 50 years or more.
It is also environmentally benign. Small hydro schemes require little or no water to be stored. Therefore, small installations do not have the same kinds of adverse effect on the local environment as large-scale hydro.
Carbon Zero Consulting, together with expert associates are able to evaluate the best technical and financial options for you when selecting biomass for heat and/or power generation.
The introduction of Feed-in Tariffs for micro hydro schemes will make this technology even more attractive. We will post details of FITs on our Home Page as they are announced by the Government.
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WASTE TO ENERGY
Carbon Zero Consulting can advise you on many alternative forms of energy including transforming waste to energy.
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