Experiment Based Performance Analysis of a Solar Absorption Cooling and Heating System in Carnegie Mellon University

The center for building performance and diagnostic (CBPD) at Carnegie Mellon University has successfully designed, installed and tested a solar cooling and heating system to assess the feasibility of solar cooling for small scale commercial buildings or residential buildings with aspects of technology and energy efficiency. This solar cooling and heating system is primarily comprised of parabolic trough solar collectors, PTSC’s and a 16 kW dual energy source double effect (2E) absorption chiller. The 2E absorption chiller driven by PTSCs was tested to produce chilled water or hot water throughout a number of clear days in summer and winter. The analyses of the experimental data defined the system performance: the efficiency of the solar collector, the capacity and COP of the chiller, and the heat transfer coefficient of the heat recovery exchanger, by using a statistical approach, based on the energy balance equation. In the solar cooling tests during July 2007 in Pittsburgh, PA, the average efficiency of PTSCs was 35% when they were operated at about 155°C for driving the 2E absorption chiller and the chiller was able to provide 8 to 14 kW cooling with COP in the range 1.0 to 1.2; the overall system efficiency is in the range 0.35 to 0.41. In the near future, this solar absorption cooling and heating test system and its operation will be integrated with the cooling, heating and ventilation units for long term utilization.