Organisation

Finance Life have built 78 apartments as part of a complex at Charlotte Quay on the Ringsend Road. The development also includes office blocks and a retail complex. The apartments were part funded by SEAI under the House of Tomorrow programme due to their energy efficient features and were the first dwellings to be supplied with energy from micro-CHP. The apartments and the micro-CHP system are currently managed by Just Property.

Project Background

As is the case for all apartment complexes, there is a large demand for heating, hot water and electricity. The use of centralised block heating facilitates the use of energy efficient and alternative technologies, such as micro-CHP.

As part of SEAI’s House of Tomorrow programme, the apartments are 40% more efficient than typical standards at the time of construction.

Project Development

Micro-CHP was the feasible and practical choice for this site given the continuous base load of electrical requirements (e.g. car park lighting, pump loads etc.) and the large amount of heat required by the 78 units. The base electrical load was calculated for the complex and designed with this in mind, given that there is no payment for export to the grid at present. The heat requirement could then be addressed with the use of a 7500 litre buffer tank which allows for the continuous running of the CHP units whilst continuing displacing electrical imports from the grid. The micro-CHP units are used in conjunction with two large boilers for back-up and extra heat demand.

Plant Operation

Two identical Baxi Dachs units were selected as the most appropriate given the base electrical loads. Combined they have an electrical capacity of 11kWe and an average thermal capacity of 25kWth. The micro-CHP meets approximately 30% of the annual space and hot water demand and runs continuously apart from scheduled servicing. The thermal performance of the units are optimised in apartments with heat metering, heat recovery ventilation, high levels of insulation and building fabric air tightness.

Technology Description

CHP, often referred to as cogeneration, is the combined production of heat and power in a single process. It takes advantage of the heat rejected in the thermo-dynamic conversion process from primary fuel to power. This heat is then supplied for useful purposes.

Combined Heat and Power

 

Micro-CHP typically saves around 25% of the energy that would have been required to produce electricity in a conventional power station and heat in separate heat-only boilers.

Micro-CHP is defined as CHP with an electrical capacity of less than 50 kW. Whereas CHP has traditionally been installed in larger sites, this scale of CHP is suitable for smaller businesses.

The benefits of CHP when compared to importing electricity and

  • using boilers to generate heat include:
  • improved efficiency of overall primary energy use,
  • energy and CO2 emissions savings,
  • independence and security of power supply.