Analysis of load profiles for Combined Heat and Power

Residential, commercial and institutional buildings use 30% and 56% of the total domestic natural gas and electricity use in Canada, respectively. Buildings use natural gas for heating and domestic hot water, while electricity... [ view full abstract ]

Residential, commercial and institutional buildings use 30% and 56% of the total domestic natural gas and electricity use in Canada, respectively. Buildings use natural gas for heating and domestic hot water, while electricity is used for lighting and appliances.

Combined Heat and Power (CHP) systems simultaneously generate electricity and useful heat. CHP systems provide environmental benefits due to their enhanced conversion of energy and the use of waste heat. A variety of CHP technologies offer heat and power generation at a wide range of capacities and heat-to-power ratios. Due to these potential benefits relative to conventional systems, deployment of CHP systems is often part of municipal GHG emissions reduction plans.

The energy, economic and environmental performance of CHP systems depends on the magnitudes and simultaneity of the aggregated heating and electricity load profiles of the buildings in a community. These, in turn, depend on factors such as the spatial distribution of building densities, building use types (residential, commercial, industrial), building thermal performance, climate, and the characteristics of the existing energy infrastructure. Since the potential performance benefits of CHP come from the simultaneous generation of useful heat and power, they are only realized when the dynamics of electricity and heat demand profiles match over time.

This study analyzes the dynamics of load profiles to explore opportunities and challenges of CHP systems. The objective of this analysis is to identify combinations of load profiles (which correspond to different building types), CHP heat-to-power ratios, and CHP capacities that optimize performance of CHP systems. CHP performance is assessed in terms of 1) the contribution of heat recovery to meet the heat demand (i.e., how much of the heat demand is met with the heat generated as a by-product of electricity generation), and 2) the amount of waste heat (i.e., heat generated as a by-product of electricity generation that is not used). This analysis focuses on the match between energy supply and demand within a community (i.e., the capability of a community to close the energy loop), and disregards efficiencies and GHG emissions factors of the potential CHP technologies. This analysis is based on a case study, the redevelopment of the Manchester District in Calgary, which vision is a triple mixed use (residential, commercial, industrial) sustainable community. This study uses heat and electricity load profiles for residential, commercial and industrial buildings from a wide variety of sources. This study provides insights on the potential impact of a transition to high performance buildings on CHP performance, optimal combinations of CHP capacity and heat-to-power ratio, as well as industry load types that offer the best opportunities for enhanced CHP performance.