Sizing a new solar hot water heater system

Getting the right size for your space and need is important when installing many different appliances and systems, including solar hot water heater systems. When systems are not sized properly, you can suffer from inefficiency and lack of supply. When sizing a solar hot water heater system, here are the two main factors we consider,

Size of the solar collectors

In order for your new solar hot water heater system to supply the amount of hot water you need, the system needs to have adequate collector coverage. The collectors of solar hot water heater systems for homes in Pennsylvania and New Jersey are typically sized as follows:

• 25 square feet of surface area is needed for a 2-person household
• For each additional family member, 12 to 14 square feet of collector surface area is necessary

Size of the storage tank

The storage tank of your solar hot water heater system holds all the water heated by the solar energy that your collectors absorbed. In an active system, you need 1.5 gallons of storage tank space per square foot of collector area.

• In general, households of two people need storage tanks with a capacity between 40 and 50 gallons.
• 3 to 4-person households have tanks around 60 to 80 gallons.
• 5 to 6-person households need a storage tank of approximately 100 to 120 gallons.
• If your household has a higher demand for hot water, you should consider a storage tank the next size up.

The experts at Smith Sustainable Design know how to size your solar hot water heater system the right way to ensure maximum performance and comfort. Call us to size and install a solar hot water heater system for your home this summer.

Positioning your solar heat panels

If you’ve decided to install a solar thermal system at your home or business, you’ll need to think about how to place your solar heat panels. Your system’s efficiency depends on how much solar energy the solar heat panels can collect, so placing the panels appropriately is a top priority. At Smith Sustainable Design, we position solar heat panels using the proper orientation and tilt for optimum performance.

Solar heat panels need to be placed in a space and direction that allows them to collect the maximum amount of solar energy each day. During a site survey, we will determine which direction is best for your panels to face. Typically, solar heat panels in New Jersey and Pennsylvania should face south. We will also consider the orientation of your roof if you’d like to have your panels mounted on the roof, and landscape features to determine how the solar heat panels will be affected by shade throughout the day.

The tilt of your solar heat panels is another important factor that helps us maximize your solar energy collection. The angle of your roof plays a part in helping your solar heat panels collect the sun’s energy to heat your water. Most panels today are mounted flat to the roof, so the roof pitch will also be the same angle as the tilt of the panels. A flat mount looks better to many homeowners than a rack mount. The angle of your roof will be used to help us determine the appropriate sizing of your entire solar hot water system.

Positioning your solar heat panels properly is crucial to the performance of your system. The solar heat panel installers at Smith Sustainable Design and specially trained to consider orientation and tilt to develop an optimal installation plan for your equipment. Contact us today to schedule your site survey.

Measuring the efficiency of solar hot water systems

Whenever you install a new system or appliance in your home, efficiency is an important factor. Different systems and appliances measure their efficiency in various units. For a solar hot water system, efficiency refers to one of two things: the thermal energy output or the amount of energy the system offsets from a conventional gas or electric system. The units used to determine the efficiency of solar hot water systems are ones you may be unfamiliar with, so let’s take a look at each.

Solar Energy Factor (SEF)

Energy delivered by the system / conventional energy input = SEF

Solar Energy Factor values range from 1 to 11, and most residential solar hot water systems have a water heater rating of 2 to 3. The higher the number, less conventional energy is being used to heat water.

Solar Fraction (SF)

The solar fraction refers to the amount of the total hot water heating load which was produced by solar energy. A higher solar factor means more solar energy has contributed to heating the household’s water. Solar factor values range from 0 to 1, and most residential solar thermal systems have solar factors between 0.5 to 0.75.

Btu/(ft²day)

Btu/(ft²day) indicates how much thermal energy is produces per square foot of collector space each day. Btu is the abbreviation for British thermal units, a measurement of thermal energy needed for water heating. Higher Btu/(ft²day) measurements mean fewer square feet of space in the collector are needed to heat the same amount of water. This rating is used for most models of solar collectors.

If you have any questions about determining the efficiency of your solar hot water system, give us a call. Smith Sustainable Design’s team of solar hot water systems contractors are happy to discuss solar options for your New Jersey or Pennsylvania home.

How much can you save with a solar thermal system?

Anytime you install a major appliance in your home, you likely compare many types to see which is the best for you. When installing a solar thermal system, many homeowners like to try to determine just how much savings it will help them achieve. To estimate your solar thermal savings, consider these factors.

Every household has different needs and different usage. How much you will save with a solar thermal system may differ from your neighbor. Your savings depends on these factors:

• Your hot water usage
• How much solar energy you’re able to collect
• System performance
• Financing and incentives
• Conventional fuel costs for your backup system
• The efficiency of your backup system
• How often you rely on your backup system

For most homeowners, a solar thermal system will save anywhere from 50% to 80% on hot water heating bills. By comparing the monthly operating costs of a solar thermal system to a gas or electric water heater, you can see how these different systems measure up to one another. Remember- solar energy costs nothing, while utility power may increase in price each year.

To estimate the yearly operating cost of a solar thermal system, you’ll need to know the solar energy factor of the system, as well as the fuel type and costs for your backup system. Smith Sustainable Design’s team of solar thermal installers can help you calculate the yearly operating costs and payback period for a new system. Solar thermal systems are a great alternative to gas and electric water heating, and can help you save hundreds on your water heating bills each year. Contact us to learn more.

Pressurized glycol solar heat systems

As we’ve discussed before, pressurized glycol and drain back solar heat systems are the two most common systems designs used today. Today, we will discuss how a pressurized glycol system works and how to care for one.

A pressurized glycol solar heat system has a closed-loop design. Unlike with drain back systems, the water you use is not passed through the collectors. A glycol and water mixture circulates through the collectors, and your hot water is warmed by heat transfer from this mixture. The glycol acts as antifreeze to prevent system components from freezing. The concentration of glycol in the system is determined carefully in order to provide adequate freeze protection for your solar heat system.

The pH of the glycol solution within your system should be checked annually. Your solution needs replaced whenever the pH falls below 7. Other components need checked regularly to ensure your solar heat system is working properly. Pressure relief valves, check valves, and automatic air vents are prone to failures and have short service lifespans. These components should be tested as part of your solar heat system’s regular maintenance routine to determine whether or not replacement is necessary.

Pressurized glycol systems require fluid changing every few years. As these fluids are under pressure, it’s best to contact a trained professional to perform this maintenance for you. Over time, glycols within your system can degrade and cause system components to deteriorate, which is one reason proper care for your pressurized glycol system is important.

Solar heat systems are becoming more common and are being utilized by more and more home and business owners every day. Pressurized glycol systems can be a useful design for your application, but require regular maintenance and care to maximize system life. If you have questions about pressurized glycol solar heat systems, please give us a call. At Smith Sustainable Design, we’re here to answer your solar heat questions anytime.

Get the facts about solar thermal water heaters

While many people associate solar power with electricity generation, not everyone knows it can be used to heat water. Solar hot water is called solar thermal, and is an energy efficient way to meet the hot water demand of your household. Solar thermal can also be used to provide cost-effective heating solutions for pools. Get the facts below to learn more about the advantages of solar thermal.

Solar thermal is cost-effective

A complete solar energy system for electricity generation may be out of your price range, but solar thermal systems are very affordable. Using solar energy to heat your water is a cost-effective way to begin utilizing natural energy to save money on your utility bills. Whether you are used to using a gas or an electric water heater, solar thermal will provide significant savings over both these traditional water heating methods.

Solar thermal is more efficient

Converting the sun’s energy to electricity takes a lot more work than simply absorbing the sun’s heat for use. Solar thermal is around 3 times more efficient than the average solar panel which converts sunlight for electricity. Hot water is also much more efficient for storing energy than the electrical storage which is used by solar panels.

Solar thermal is a good investment

Considering their cheaper price tag and higher efficiency, solar thermal systems can be a much better investment financially. Without the high cost of a solar electricity system, solar thermal systems have a much shorter payback period.

If you’re interested in using solar energy in your home, solar thermal is an affordable way to do so. Reduce energy costs by meeting your home’s hot water demand using the sun’s energy instead of your utility provider’s. Smith Sustainable Design installs solar thermal systems for homes as well as businesses. If you want to learn more about solar thermal for your home, feel free to contact us.

Drain back options for solar hot water systems

Drain back solar hot water systems are one of the most common types of solar thermal systems used today. In short, they utilize two temperature sensors to control the system. When rising temperatures are detected in the solar collectors, cold water from the storage tank is pumped through, absorbing heat as it’s pushed through. The water then flows back into the drain back tank to maintain a certain temperature.

Drain back solar hot water systems can be designed a few different ways:

Type 1 drain back design, often called a two-tank system, uses a full size solar hot water storage tank, and a separate solar storage tank. This design can be used for large or small systems. When hot water is used in the home, it passes through the heat exchanger into the hot water heater, preheating the water and minimizing the energy used by the regular water heater.

Type 2 drain back design uses a solar hot water heater with a built-in heat exchanger. This one-tank system uses one pump to run the collector loop, and holds the volume for solar storage and for the regular hot water heater. They are used mainly for smaller residential systems.

Type 3 drain back design is used for similar applications, and has a heat exchanger located within a small reservoir tank, making it compatible with gas or electric conventional hot water heaters. A second pump is usually needed to circulate water within the system.

The advantages and disadvantages of each system design vary by application. Depending on your home and the configuration required, one solar hot water system design may offer better results and more energy savings. The experts at Smith Sustainable Design will plan your solar hot water system design using the most appropriate configuration for your home. If you have questions about the drain back options available, please give us a call.