Solar Hot Water (SHW) inputs

Engineering Inputs

Patrick Chopson avatar
Written by Patrick Chopson
Updated over a week ago

Solar Hot Water (SHW) systems leverage sunlight for generating heat to provide hot water, instead of using electricity from the power grid or gas. SHW consists of a few primary components; collector(s), heat exchanger, and a backup heater for cloudy days. cove.tool uses the information relating to the solar collector to provide generative energy results for your building analysis helping provide a more sustainable solution for hot water.

(Source: AU Department of Resources, Energy, and Tourism)

SHW Collector Surface Area: Total Surface Area of the Collector

The collector surface area is the total surface area of the exposed absorber plate. The SHW collector is a solar thermal panel, similar to a photovoltaic (PV) panel, but instead of transferring sunlight into usable electricity, it transfers the radiant heat to the water. Enter the collector surface area (not the roof area it covers) into this input field.

SHW Collector Angle:

The angle in degrees between a horizontal plane and the collector as it is installed. Similarly to solar panels, if you live in the northern hemisphere, you would point your panels due south to capture the maximum amount of sunlight, and due north is in the southern hemisphere. For installations on a pitched roof, this is typically the angle of the roof as they are installed directly onto the roof.

SHW Collector Efficiency:

The percentage of efficiency for the heat generation is used versus loss specific to the type of collector for your selected SHW system. The input value is a number between 0.0 and 1.0.

SHW Systems at a Glance

SHW systems can come in two types; active or passive. Active systems have two variations; direct circulation best for climates with less frequent freezing, or indirect circulation for freezing climates. Passive systems are typically less expensive and tend to last longer, but also less efficient. Passive systems also have two variations; integral collector-storage with less frequent freezing, and thermosyphon that relies on natural thermal fluctuations in the water temperature to function properly. The U.S. Department of Energy offers a more detailed description of solar hot water systems.

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