University Square Apartments
Philadelphia Pennsylvania University
University Square is a HUD subsidized community of adults 62+, comprised of 442 apartments. Because energy costs are a large portion of its operating budget, building management continually seeks ways to reduce energy expenses for its tenants as well as reduce the property’s impact on the environment.
CHP project developer Dalkia Aegis, EDF Group applied for a grant on behalf of the building under the State of Pennsylvania’s Green Energy Works! program. After performing a detailed energy analysis, which demonstrated compelling energy savings and reduced environmental impact with CHP, University Square was awarded a 50% grant for a Combined Heat and Power (CHP) system from Dalkia Aegis, EDF Group, which then engineered and installed two turnkey 75kW packaged CHP systems to provide electricity and heat/hot water to the multi-unit building.
CHP System Description
The CHP system, designed and installed by Dalkia Aegis, EDF Group, consists of two Aegen ThermoPower 75LE Cogeneration Modules, which feature natural gas-fired engines, supplying a total of 150 kW of electricity. The main electrical distribution panels in the building receive the cogenerated electricity, which is then distributed to meet 16% of the total building load. Electricity from the grid services the remaining load.
The system was easily located in a mechanical room adjacent to the boiler room, and is equipped with a state-of- theart Windows-based microprocessor for automatic, unattended and remote monitoring by Dalkia Aegis to ensure system is operating at optimum parameters.
Use of Recovered Heat
Heat produced in the Aegen ThermoPower unit’s engine and engine exhaust is captured through various heat exchangers located in the oil cooler, engine jacket, and exhaust manifold heat exchangers. This captured useable heat is then transferred to University Square’s domestic hot water and comfort space heating loops. The CHP system meets 34% of the building’s total space heating and domestic hot water demand.
Maintenance and Operational History
The Aegen ThermoPower unit was installed and began operation in 2010, and has been running 20+ hours per day. The building contracted with Dalkia Aegis to maintain the CHP system that includes remote monitoring of the system around the clock. This monitoring allows Dalkia Aegis to detect and correct any disturbances and other system problems before they can impact the savings from the CHP system.
Costs and Benefits
The initial cost to install the University Square CHP system was approximately $500,000 with a 50% grant from the State of Pennsylvania’s Green Energy Works! program. Overall, University Square will save 11% in energy operating costs. These savings result in a projected payback of 7 years but by incorporating the grant in the calculation, the payback period is reduced to 3.5 years. Because the building owner is dedicated to finding innovative ways to reduce its energy usage and carbon footprint, they appreciated the 550 ton annual reduction in carbon dioxide emissions which resulted from installing the high-efficiency CHP system, which is equivalent to removing 93 cars from the road. (source:EPA calculator)