TMC to Harness Sun’s Rays

Tucson Medical Center is poised to begin harvesting energy from the sun for the first time this summer.

A nonprofit hospital, TMC is installing a new cogeneration system that is far more efficient than standard photovoltaic panels, combining both electric and solar hot water generation in a single array.

Traditional photovoltaic panels allow most of the sun’s energy to dissipate as waste heat. The Cogenra system being installed at TMC, however, will instead capture the heat that comes off the back of the photovoltaic cells and then transform that energy into the form of hot water. That ability, happily, will boost savings in a time of rising utility costs while reducing greenhouse gases more significantly.

The system is being installed on the roof of TMC’s power plant, with a crane moving some of the equipment into place this week.

The location was chosen in part because of the plant’s demand for large quantities of hot water. The system will generate enough energy to heat 5,300 gallons of hot water per day for the power plant boilers, which generate steam for things such as heating, laundry processing, food preparation and sterilization of instrumentation. The system will reduce demand for both the electrical and natural gas utilization in the power plant.

“We use thousands of gallons of hot water every day. As a community hospital, decreasing our natural gas consumption and energy bills is very important. Solar cogeneration offers a way to address those needs,” said Richard Prevallet, vice president of facilities and construction at Tucson Medical Center. 

“This is our first renewable energy project and it’s encouraging to see that the economics of solar cogeneration allowed us to implement a renewable energy solution, helping us save money, while also helping the environment,” he said.

The system is expected to go live in June 2012. It is expected to save more than $9,500 a year in energy costs and the company anticipates it will offer a return on investment in less than five years.

“Healthcare is an ideal industry for solar cogeneration implementation,” says Gilad Almogy, CEO of the California-based Cogenra Solar, which is entering the healthcare market for the first time with the TMC installation.  High hot water demand and energy bills, as well as a number of environmental industry mandates, help position hospitals to gain from solar cogeneration, he said.

Cogenra, which does commercial work only, has also completed installations for commercial buildings at Facebook, as well as locally on the University of Arizona campus.


  1. David Meyer says:

    Cooling the photo voltaic panels will also make them more efficient. Next, turbines in space to harness the solar wind.

  2. Patricia Tanrioger says:

    So good to see solar energy being used in Tucson, a city with 330 days of sunshine a year! Good work, TMC!

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Tucson Medical Center | 5301 E. Grant Road | Tucson, Arizona 85712 | (520) 327-5461
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