Solar Hot Water

Solar Hot Water
Solar combi system supplimenting radiant floor and domestic hot water

Monday, February 7, 2011

Heat Exchangers!

There are exceptions but 99.9% of solar hot water systems require the use of a heat exchanger.

Heat exchangers are made to transfer heat from a source (solar collectors) to a delivery or storage system (tank). Heat exchangers are classified as liquid to liquid, air to liquid or air to air. Heat exchangers can be designed for cooling or heating, although in the solar industry they are used primarily for heating.Liquid to liquid heat exchangers can be as simple as a coil of tubing submerged in a tank of water. This is called a single wall heat exchanger since only one wall of tubing seperates the two liquids. A double wall heat exchanger is required if the heat is being transferred from a non-potable liquid (glycol) to a potable (drinking water) system. These exchangers are designed so the fluids can never mix.

One example of a double wall heat exchanger would be AAA Solar's Quad Rod heat exchanger. The quad rod is a double wall heat exchanger made completely of copper with brazed fittings. Here are some pictures of a Quad Rod heat exchanger.

3' Quad Rod heat exchanger

Cut-Away



A simple way you would use a heat exchanger would be to heat water in an existing water heater. A system for heating an existing water heater would include one 4'x10' collector, a heat exhanger, two pumps and a controller. In this system, a heating fluid (glycol) is circulated through the collector and the heat exchanger with a pump. This can be done with an AC pump that is wired to a controller with sensors at the collector and water heater or is can be done with a DC pump that is wired to a small PV panel. the water from the tank is then circulated through the heat exchanger with a pump as well. The two fluids should be flowing in opposite directions for maximum heat transfer. While the sun heats the glycol and the heated fluid passes through the heat exchanger the heat is transfered to the water that is passing through the heat exchanger at the same time. As the water from the tank circulated the tank is heated and will only "fire" if the solar is not able to keep up with demand.

For more information on heat exchangers and specific products please visit http://www.aaasolar.com/.

10 comments:

  1. The heat exchanger should be designed for your needs and the water treatment chemicals being used to treat the tower water. If you are thinking of switching to more aggressive chemicals to remedy a problem such as algae within the cooling tower, check with the heat exchanger manufacturer to confirm its compatibility with the plates and gaskets.

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  2. ALB Associates offers all type and size of Shell and Tube Heat Exchanger. We are one of the leaders in heat exchangers market. Search our website in this section to find more information about our Shell and Tube Heat Exchanger products.

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  3. Hi,

    Heat exchangers are off the shelf equipment targeted to the efficient transfer of heat from a hot fluid flow to a cold fluid flow, in most cases through an intermediate metallic wall and without moving parts. It is the function of a heat exchanger to transfer heat as efficiently as possible. Thanks...

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  4. Indus Infra Engineers provides manufacturers, suppliers, exports, and imports Heat Exchangers.

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  5. Dowfrost HD is a higher rated Solar Panel Glycol. Dowfrost HD provides the composition stability at higher temperatures and will provide freeze protection in the cold months.

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  6. Tell Them Everything
    Be sure to communicate all pertinent information regarding your application to the manufacturer when you request a quotation. Two liquid streams, referred to as the "hot side" and the "cold side," go into and come out of a heat exchanger (figure 1). As a result, there are four temperatures to consider when sizing the heat exchanger: hot side inlet, hot side outlet, cold side inlet and cold side outlet.

    The minimum information needed to size the heat exchanger for both the hot and cold sides are: fluid names, flow rates, inlet temperature, outlet temperature, operating pressures and maximum pressure drop allowed across the unit. For fluids that are uncommon or proprietary, physical properties such as viscosity at inlet and outlet temperatures, thermal conductivity, specific gravity and specific heat will be needed. Most manufacturers have a design questionnaire available for you to use when collecting data for a heat exchanger application and would be eager to furnish you with a copy.
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  7. Hey friend I want share with you something hope this one good for you. Be sure to communicate all pertinent information regarding your application to the manufacturer when you request a quotation. Most manufacturers have a design questionnaire available for you to use when collecting data for a heat exchanger application. There is some basic data needed for the fluids on both the hot and cold sides to properly size a plate and frame heat exchanger. They include the fluids names, the flow rates of each, the physical properties (specific gravity, specific heat, thermal conductivity and viscosities) if the fluids are other than water or glycols, design pressure and the maximum allowable pressure drops for the heat exchanger. Please include any potential issues such as erosion, particulates, fouling, etc., if applicable.
    industrial engineering info

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  8. How about when it will be used in the production of modern day cooling towers?

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  9. The coin folders are one of the major supplies that helps all the collectors stash their coins, and in a very safe manner.
    The increasing popularity of the coin albums has made the manufacturers increase the number of leaflets in the album.
    For more: Collector supplies

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