SAV-i Issue 33

SAV LoadTracker – taking CHP to the next level

If you thought CHP was inflexible – take another look

Combined Heat and Power (CHP) is a tried and tested low carbon technology that can make a significant contribution to reducing carbon emissions from heating and power generation, compared to a traditional mains power/boiler arrangement. However, the inflexibility of traditional CHP designs has tended to impose constraints on the environmental benefits that can be achieved.

Bjarne Bogner, CEO EC Power, “The stone age did not end because of a lack of stones. The fossil fuel age may as well end before a lack of fossil fuels.”

SAV’s LoadTracker CHP has been specifically designed to deliver maximum flexibility through both its modular configuration and the ability of each unit to modulate down to 40% of its full electrical power output.

Modular configuration for a range of applications

Just as modular boilers have largely replaced single large boilers to provide greater flexibility, so the modular configuration of LoadTracker CHP delivers the same level of flexibility, compared to traditional CHP.

Modulating in response to change

Unlike traditional CHP, LoadTracker is dynamic and can modulate the electrical output – virtually instantaneously – down to 40% of its full power output in response to changing demand. As a result, LoadTracker CHP makes optimum use of the most expensive energy source, the electricity, to achieve maximum energy and cost saving benefits.

CHP where you thought it couldn’t go

SAV LoadTracker units are available in two sizes:

  • 15kWe/30kWth
  • 20kWe/40kWth

Three LoadTracker CHPs in a plant room.

And they can be combined in configurations of up to 5 units to serve much higher demands – making them ideal for use in a wide range of applications, including:

  • Multi-residential housing
  • Student accommodation
  • Schools
  • Nursing homes
  • Hospitals
  • Leisure centres

… and many more

Facing up to the challenges of CHP

Specifying CHP can bring a range of challenges but LoadTracker CHP has been designed to address many of these challenges, enabling building services engineers to deliver the best solution for their client without compromise.

CHALLENGE 1:

Conventional, fixed-output CHP units are usually sized to match the site base load. Consequently, they do not contribute to site usage beyond base load, so that energy savings are relatively small.

SOLUTION:

By tracking site demand and modulating their output, LoadTracker CHP units ensure that the electricity generated never exceeds demand, so there is no need to ‘dump’ heat or sell surplus electricity to the grid at unfavourable rates. It also means the CHP maintains efficiency when other energy-saving initiatives (e.g. installing low energy lighting) reduce electrical consumption.

Consequently, LoadTracker CHP can be thought of as ‘plug and play’, so that units are matched approximately to the building loads and will then ‘self-learn’ the building demands profile and self-modulate to suit conditions

CHALLENGE 4:

To achieve the best possible performance from a CHP installation, careful attention must be given to integration of the CHP within heating circuits.

SOLUTION:

To address this issue and optimise the system, attention needs to be paid to the whole system design, rather than simply the central plant room design. In particular, the system should be designed to meet the requirements of CIBSE Guide AM12, which identifies the following key objectives:

  1. The CHP unit should operate in preference to the boilers at all times.
  2.  When boilers are in service, they should not prevent the CHP from operating at maximum output.
  3.  Heat recovery from the CHP unit should be optimised.
  4. The CHP unit should always be able to generate heat even under part-load heating conditions.
  5.  The building heating system should be designed so that return temperatures do not result in the CHP unit shutting down unnecessarily.

LoadTracker CHP can be incorporated into a heating system either in series or in parallel with the boilers.
Just as importantly, SAV works closely with specifiers on all projects, reviewing mechanical drawings and advising on the best possible design for each project.

LoadTracker in action

The Christie Unit at the Salford Royal Hospital is one of a network of Christie radiotherapy centres. It has very high energy demands and required an efficient means of producing heat and power to comply with the Building Regulations.

The solution was to install a LoadTracker CHP, which is delivering savings in annual energy costs of nearly £7,000, compared to a conventional mains supply/boiler system, with a 10% reduction in carbon footprint.

A single LoadTracker 15kWe/30kWth unit has been installed at the site, capable of supplying 92% of heating and hot water demand and 20% of electrical demand.

mains power boiler cost vs chp

University of Reading, Mansfield Halls Student Accommodation

Mansfield Halls near Reading provide accommodation for students at Reading University. In order to achieve low running costs and carbon emissions the Halls are making use of 3 x LoadTracker CHP with 15kWe/30kWth capacity. One of the units serves 147 bedrooms and 14 studios, while the double module serves a further 457 bedrooms.

Combined, these meet up to 75% of domestic hot water demand and up to 9% of electrical demand, delivering savings in energy costs of about £2,500 per month, compared to a mains supply/gas boiler arrangement, with a reduction in carbon emissions of 8,768 kg.