All FAQ
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Many regions seldom experience freezing temperatures while others deal with them much of the year. Chances are, if you live in climate where the temperatures drop below freezing frequently, the solar heater you purchased and installed is already geared to handle the changing conditions.Many of the regions that experience the coldest temperatures don’t lack sunlight during the winter, so ensuring that your solar hot water heaters functions year round is mainly an issue of freeze prevention.First, the pipes, or as little as possible of them, should not be exposed. This is not as necessary if you operate a closed loop system with antifreeze. However, some closed loop systems circulate water as the heat transfer liquid which could freeze even during the day.Closed loop systems pump a heat transfer liquid such as antifreeze into the solar collector. This liquid is heated by the sun and then pumped back to the storage tank where a heat exchange transfers the heat energy to potable water. Antifreeze will not fail during cold weather conditions, but you before the onset of winter you should check the amount of it. Any failure of the system during the winter could deprive your home of hot water.water automatically drains out of the collector when there is no sunlight and no further water is pumped into it, drain back systems have a built-in freeze protection. If temperatures are below freezing even when the sun is out, drain back systems could still be at risk of freezing.
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Provide support structure for the collector array of aluminum, stainless steel, or other corrosion-resistant approved material . Furnish a support structure which secures the collector array at the proper tilt angle with respect to horizontal and orientation with respect to true south. Consideration should be made to mounting collectors parallel to the pitched roofs. The collector tilt angle may vary by +/- 25 degrees, and the azimuthal angle may vary by +/-45% from the optimal tilt and azimuth. Provide a support structure that will withstand the static weight of filled collectors and piping, wind, seismic, and other anticipated loads without damage. For heavy systems, such as integral storage collectors, provide structural reinforcement for the roof across at least four rafters and provide verification that the structural modifications proposed are satisfactory. Provide a support structure which allows access to all equipment for maintenance, repair, and replacement. Neoprene or EPDM washers shall separate all dissimilar metals. Depending on system type, supports for solar array could terminate in ballast blocks to avoid roof penetrations.
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1.PIPING SYSTEMProvide a piping system complete with pipe, pipe fittings, valves, strainers, expansion loops, pipe hangers, inserts, supports, anchors, guides, sleeves, and accessories with this specification and the drawings. Pipe shall be designed to observe limits on flow velocity, pressure drop, and gauge pressure associated with the pipe type and characteristics. Provide, install and test the piping. Provide piping flow rates below 5 feet per second. Piping shall be Type L or Type M copper tubing, ASTM B-88, with 95-5 tin-antimony soldered joints. If cold water piping supplying the SWH system is of another type, such as PVC, it shall be replaced within 10 feet of the SWH system with copper to avoid bulging and rupture due to proximity to the higher temperatures of the solar system. 2.Pipe InsulationFurnish interior pipe insulation and coverings such as Armaflex, Insul-Tube, Rubatex, or approved equivalent. Provide outside array piping insulation with a capability of withstanding 250 degrees F, except that piping insulation within 1.5 feet of collector connections shall be capable of withstanding 400 degrees F. Protect outside piping insulation from water damage and ultraviolet degradation with a suitable outer coating manufactured for this purpose (aluminum, sunlight resistant PVC or approved equal). 3. Calibrating Balancing Valves (for multiple collector banks)If systems are proposed with multiple collector banks, provide calibrated balancing valves suitable for 125 psig and 250 degrees F service. Furnish calibrated balancing valves with bronze body/brass ball construction with seat rings compatible with system fluid and differential readout ports across valve seat area. Provide readout ports fitted with internal insert of compatible material and check valve. Provide calibrated balancing valves with a memory stop feature to allow valve to be closed for service and reopened to set point without disturbing balance position, and with a calibrated nameplate to assure specific valve settings. Provide calibrated balancing valves and ball valves at the outlet of each collector bank. The balancing valves are specified to allow the array to be flow balanced. The ball valves are required to enable the array to be disconnected for maintenance or repair. This requirement for balancing valves is not applicable to systems of only one collector bank, where balance of flow is not an issue.4.Pressure GaugesProvide pressure gauges with throttling type needle valve or a pulsation dampener and shutoff valve. Furnish a 3-1/2 inch minimum dial size.5. ThermometersSupply thermometers with wells and separable bronze sockets.6.Pipe Hangers and SupportsSupport and hang piping so that the weight of the piping is not supported by drywall , siding, or other building members not designed to bear load. Support piping so that thermal expansion and contraction of pipe lengths is accommodated. 7.ValvesProvide valves compatible with the piping. Ball valves shall be used for shutoff, with full port, bronze body, bronze ball and teflon seat. Bronze hose-end gate valves shall be used for draining low points of piping.8.NameplatesSecure to each major item of equipment the manufacturer's name, address, type or style, model or serial number, and catalog number on a plate.
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Design, furnish and install new solar water heating (SHW) systems for the heating of domestic water. The solar water heating system offsets the use of natural gas, propane or electricity by preheating water before the conventional domestic hot water system. System types incorporating both freeze-protection and overheat protection are required. Freeze protection is not required if climate is non-freezing, but overheat protection required in all systems. Supplied equipment must be rated and warranted to withstand and operate under lowest-record-low and highest-record-high temperature for the location. It is often the intent to use the system for educational purposes related to the benefits and use of renewable energy, so appearance and quality are considerations in design decisions.Solar collectors are to be mounted on the roof or on the ground as suitable for the type of SHW system and needs and limitation of the building and site. System must be of a type suitable to the climate of the site. For systems proposed not under passive control, control each system by a simple differential temperature controller. Provide a separate solar water heating system for each building unit designated. Each of the solar systems is to incorporate the existing electric water heating system as its auxiliary subsystem. In the event that the existing electric water heater is in need of repair or replacement, the contractor may propose to repair or replace the electric water heater under the scope of this project. Include with each system, components that consist of a solar collector array, array support structure, storage tank, interconnecting piping and fittings, tempering mixing valve, flush-and-fill valves, pressure relief valves,and as required by the system type, any necessary pumps, controls or heat exchangers, as well as all other accessories and equipment required for the proper operation of the solar system.Include with system all labor, supervision, equipment inside and outside the building, tools, materials and incidentals necessary to design, procure, install, checkout and place into operation a complete solar water heating system ready for use for the building.
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