As carbon reduction targets become more strict and fuel prices continue to rise, it has never been more crucial that heating and hot water systems achieve maximum efficiency.
Interest in energy management has increased significantly in recent years because of new targets to reduce carbon emissions and improve energy performance. Legislation, such as the Ecodesign of Energy-related Products (ErP) Directive, now plays a key role in influencing how manufacturers and system operators view energy consumption and how they intend to reduce it.
The installation of low-carbon technologies is a good step towards enhancing energy efficiency. But when looking to implement a combined heat and power (CHP) solution in a building, it is vitally important to take into account the energy efficiency of the technology used – both now and in the near future – in order to ensure it performs to its full capabilities.
A CHP installation will only maximise its efficiency to the full if it is designed to use 100% of the heat generated. Although the Combined Heat & Power Quality Assurance Programme allows a proportion of the heat to be rejected throughout the year, ideally all heat should be used.
With premium efficiency levels and cost savings the ultimate objective for such an arrangement, it is vital that no heat is rejected – this could jeopardise the system’s effectiveness and significantly increase the payback period for the end user.
However, it is also important to look past current CHP requirements and consider how any future energy-saving technologies scheduled to be installed could affect the CHP system’s performance. As the ErP Directive’s second phase rolls out in 2015, for example, any application using fans or motors will have to meet improved minimum efficiency standards, and these could have a significant effect on the sizing of CHP modules.
To ensure a CHP system is correctly sized, you must first take the energy data of all heating, hot water and electrical technologies – both already installed and planned in the near future – into consideration during the design stage. Once this has been calculated, a CHP system should be sized either to the thermal baseload of a project or 20% of the peak load to allow for maximum efficiency.
Correct sizing of a CHP system is essential to ensure the balance between maximising savings and providing useful heat and electricity. It is also vitally important that these metrics be measured over the full lifecycle of the system. A well thought-out design will increase the likelihood of a favourable return on investment, which will – in turn – lead to quicker payback on the initial financial outlay.
Ben Richardson is CHP commercial technology consultant at Bosch Commercial and Industrial Heating