Upon returning from the collectors, the glycol enters the coil of a high performance heat exchanger, located adjacent to the solar storage tank. The heat exchanger is a shell and coil type with four copper coils enclosed in a copper shell. The glycol flows in parallel through the four coils. This, together with the small diameter tubing to and from the collector, accounts for the pump being of much larger size than for the ICS system. Water, inside the shell, circulates from the heat exchanger to the solar storage tank via natural convection, driven by the temperature difference between the hot glycol and the colder solar storage tank water.
Energy is removed from the top of the auxiliary tank.
Instrumentation and Measurements Instantaneous measurements were logged every 15 seconds. The latter data files are useful when one is interested in the details of the draws, and are indeed needed to calculate the energy draws accurately. These are described separately by section below. Each data record is time stamped with with the current or averaged Mountain Standard Time. The weather station consists of two pyranometers used to measure horizontal and tilt radiation, a wind speed anemometer, a wind direction indicator, and a shielded, outdoor ambient temperature sensor.