ECL Closed Loop Solar Water Heating Systems

ECL Closed loop systems use heat-exchangers that circulate heat-transfer fluids through the panels and feed pipes. ECL closed-loop systems keep transfer fluid separate from the potable water through utilization of a heat-exchanger.

The ECL system works essentially by having the sun heat fluid that is pumped through the solar collectors. The solar heated fluid flows through a copper or stainless steel heat-exchanger located near the solar storage tank. The heat from the solar fluid transfers to the potable water within the solar storage tank. On some retrofit systems, another small circulator pump may be used to circulate the water through the potable side of the heat exchanger.

The anti-freezing heat-transfer fluids can withstand freezing temperatures, allowing the system to operate during periods when there is the greatest temperature difference between cold incoming water, and temperatures reached in the solar collectors. The system can have the greatest performance benefits at this time. Also, if maintained properly, these systems will not corrode or scale the passage ways in the solar collectors and pipes. Closed-loop systems tend to have the lowest overall operating costs --other than passive systems-- and are especially adapted to work in regions with extended periods of freezing temperatures, and commercial environments that are used daily (including weekends).

If hard freezes are common in your area, an ECL Closed-Loop System utilizing a nontoxic anti-freezing heat-transfer fluid is a better choice than

• an open-loop system that circulates potable water and is susceptible to freeze damage if the freeze-protection apparatus or procedure fails
• a drainback system where the lines (and entire solar panel loop) cannot be plumbed with drain slopes of 1/4inch per foot or steeper

A properly installed closed-loop system will operate for years with little or no service. A change of the anti-freeze is recommended once every 5 to 7 years or so. If your solar system is exposed to regular, long term intervals of stagnation due to a home vacancy (vacation etc) or system shutdown, the heat-transfer fluid may need changed sooner --as often as every 3 years.

system configurations

Closedloop systems are configured according to energy demands, solar energy availability and other factors at the point of installation. Closed-loop systems generally consist of at least these parts:

• 1: goldline-sb SB sensor, 10K
• 2: maidomist-71 MaidOMist Air Vent No.71
• 3: sensor wire
• 4: taco-005f2 Taco 005F2 Cartridge Circulator
• 5: watts-100xl4 T/P Pressure Relief Valve 212F,150psi
• 6: goldline-sb SB sensor, 10K
• 7: watts-100xl4 T/P Pressure Relief Valve, part of existing tank No.18
• 8: letro-sl2dw3 Letro SL-2DW3 Thermometer
• 9: watts-70a Watts 70A Tempering Valve
• 10: hot water output
• 11: cold water feed line
• 12: knob adjusts water temperature output
• 13: tomlinson-c-75 Thomlinson Quadflow bypass "H" valve
• 14: other-s480-075 NIBCO S-480 In-line Check Valve
• 15: solar panel inlet
• 16: watts-100xl4 T/P Pressure Relief Valve 212F,150psi
• 17: ksp-ks-40 KS-40 Crystal Clear Flat-Plate Solar Collector
• 18: existing hot water tank, 40 to 60 gallon, electric or gas (optional)
• 19: rheem-rhm80hx Rheem Storage Tank, 80gal with internal heat exchanger*
• 20: goldline-gl30 Goldline GL-30 differential controller
• 21: other-p570k-100lm pressure gauge
• 22: amtrol-4un87 Amtrol Expansion Tank
• 23: letro-flow2s Letro LDF357B flowmeter

not shown:

• copper piping
• pipe insulation
• heat-transfer fluid
• transfer fluid "fill tree" consisting of 2 spigots
• two tank systems should have a bypass valve or 3 shut-off valve "H" configuration

* - a regular hot water tank with an external heat exchanger and a second stainless steel circulator can take the place of a tank with internal heat exchanger. This configuration is common with retrofitting systems, such as when converting draindown systems to closedloop systems.

sizing systems

For best results, systems should be matched according to energy use patterns.

King Solar offers these closed-loop system kits to get you started saving energy:

• ECL-4 Solar Water Heating System for 3 or 4 people, powered by 110VAC

King Solar offers closed loop systems that work completely off of the electric grid. These systems are great for hot water heating in remote locations and where electrical power is intermittent.

Choosing a domestic or commercial solar system that best fits your circumstances can be a challenging exercise. If you are uncertain, the best thing to do is send us your requirements.

Tell us:

• how the solar hot water heating system will be used. For example, will it be used in a home or as part of a boiler system in a commercial environment
• how many gallons of hot water are used per day. We can approximate by knowing how many people live in the residence, the type of residence (house,duplex etc), or how much heat is created per day by a boiler etc.
• where are you geographically located

Contact us for a price quote. We will reply within 48 hours with a suggested set of equipment specifications to meet your alternative energy needs.