Re: Ellen's residential chiller application. Question arises in my mind what thought process was behind choosing a chilled water approach for 3,000 square feet vs. split system DX, one system per floor.
Re: Ellen's situation directly; appears to be two problems. One: system design, and possibly structural/architectural design...HVAC can't keep up with heat gain. Two: high failure rate of parts that should not be expected to fail so soon after installation.
The passive solar aspect also piques my interest...how much is this penalizing the house during the hot months? And what exactly does this passive element consist of? Large areas of glass?
Psychrometrics: the very foundation of HVAC. A comfort troubleshooter's best friend.