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Solar Water Heating Systems

Lee Layton, P.E.


Course Outline

Starting with the basics of solar radiation, this course reviews all faucets of a solar water heating systems.  Following a review of solar radiation, each component of the solar water heating system is covered including solar collectors, storage tanks, mixing valves, controllers, and expansion tanks.

The approach to designing solar water heating system is covered including calculating water heating demand and sizing systems.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

After taking this course you should,

Intended Audience

This course is intended for anyone who is interested in how solar water heating systems can be used to reduce electric energy consumption and to reduce greenhouse gases.

Benefit to Attendees

This course will help the reader to understand how solar water heating systems work and how they can be applied in a residential application.

Course Introduction

The world is increasing interested in reducing global warming because of the belief that it may be a real threat and we must find ways to reduce carbon emissions to protect the environment.  As a result, there is a heightened interest in renewable energy production that can reduce the future demand for coal and natural gas fired power plants.  Renewable power production technologies such as wind farms, photovoltaics, geothermal, hydroelectric, and biomass systems are all receiving a lot of attention.  Another, less costly alternative, is solar thermal water heating systems.

The term “solar power” can be used to denote either solar thermal systems or photovoltaic systems.  Photovoltaic systems generate electricity by using the interaction of sunlight with a semi-conducting material, which frees electrons in the material to create an electric current.  In contrast, solar thermal systems use the heat generated by sunlight to heat air or water. 

One of the most cost-effective ways to include renewable technologies into a building is by incorporating solar hot water.  A typical residential solar water-heating system reduces the need for conventional water heating by about two-thirds. It minimizes the expense of electricity or fossil fuel to heat the water and reduces the associated environmental impacts.

Solar water heaters use the sun to heat either water or a heat-transfer fluid in the collector. Heated water is then held in the storage tank ready for use, with a conventional system providing additional heating as necessary. The tank can be a modified standard water heater, but it is usually larger and very well insulated. Solar water heating systems can be either active or passive, but the most common are active systems.

Solar collectors are the key component of active solar-heating systems. Solar collectors gather the sun's energy, transform its radiation into heat, and then transfer that heat to water, solar fluid, or air. The most common types of solar collectors are flat-plate collectors, evacuated-tube collectors, and integral collector-storage systems. Flat-plate collectors are the most common solar collector for solar water-heating systems in homes and solar space heating. A typical flat plate collector is an insulated metal box with a glass cover and a dark-colored absorber plate. 

In this course, we will review the basics of solar radiation, explore system types as well as collector types, and review the methodology to properly size a solar water heating system.

Course Content

This course content is in the following PDF document:

Solar Water Heating Systems

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Course Summary

This course has reviewed the basics of solar hot water systems, including the components, calculations and sizing criteria for a residential system.  Solar thermal systems are one of the more cost cost-effective renewable projects for a residential application.  Still, it is not cheap.  In 2009, solar hot water systems for residential applications cost between $5,000 and $8,000.  With a solar factor of 50% these systems will save about $300 per year on water heating costs, so the payback is long.  Federal tax credits and reduced construction costs may make the economics better in the future.  However, for many people, the environmental benefits outweigh the economic evaluation and we are likely to see more roof top units in the future. 

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.