Cli-mate CLI-AP30 Spezifikationen PDF herunterladen (Seite 20)

During other periods of stagnation, the pressure in the system will rise, especially if there is any steam

formation, but the same vertical loss still applies, so while the pressure may increase from 40 to 60 psi at

the pump station, the collector with a 40’ vertical height will only be about 40 psi.

d) Flash Point: The flash point of a fluid is the lowest temperature at which vaporization can occur to form a

mixture in air that can be ignited. Propylene glycol has no measurable flash point in concentrations less

than 80% and the flash point of J.C. Whitlam Hi-Temp is more than 50

F above the wet stagnation

temperature of the collector. Propylene glycol based heat transfer fluids (DOW Frost and Clariant) do not

have a measurable flash point. For more information on heat transfer fluids see Appendices 10-17..

3.6.3. Correct System Sizing to Avoid Overheating

a) Avoid Excessive Heat Output: The system should be sized so that overheating of the tank is difficult to

achieve in a single day, even during hot, sunny periods. If the system is over-sized, so that stagnation

occurs often during summer months, the system must be able to stagnate repeatedly without damage or

heat transfer fluid degradation. Using stagnation as a daily means of dealing with an oversized system is

NOT recommended.

✖ Gradual loss of vacuum in evacuated tubes over time during normal use is not eligible for warranty claims.

3.6.4. Adjusting Collector Angle to Reduce Overheating

a) Increase Angle to Reduce Summer Output: Apart from installing a smaller collector, a good method of

reducing summer heat output is to angle the collector for optimal winter absorption. This is achieved by

installing the collector at an angle 15

-20

above the latitude angle. This angle corresponds closely to the

angle of the sun in the sky during the winter, thus maximizing winter output. Conversely, during the summer

when the sun is high in the sky, the relative surface area of the collector exposed to sunlight is reduced,

lowering overall heat production by about 20-25%. See also 3.6.3 above.

3.7. Multiple Collector Connection

3.7.1. Connection of Multiple Collectors

a) Connecting Collectors in Series: Apricus recommends a maximum flow-rate of 4 gpm (15 L/min)

through any Apricus collector. This is for three reasons:

i) Excessive high flow rates can “scrub” the walls of the copper header, wearing it away.

ii) High flow rates greatly increase the pressure drop, requiring a much larger circulation pump, wasting

electricity.

iii) Peak 30 tube collector output is about 6141 Btu/hr (1.8 kW), therefore, the maximum temperature

rise per pass through the collectors will be 15.6

F (8.6

C) at the maximum flow rate specified above. A

faster flow rate provides no major benefit and may result in the pump dropping below the pump delta-t

off (dTMin) setting and causing the pump to cycle ON/OFF.

iv) Thermal expansion of more collectors in series could cause buckling of the copper header during

periods of stagnation.

Apricus OG-300 systems have a maximum number of 60 tubes in series and a maximum flow rate per

AP-30 collector of 1.0gpm

As described earlier in section 3.5, the use of a variable speed pump control is highly recommended. The

maximum flow-rate outlined above should not be exceeded by the pump, even at 100% flow during variable

speed control. For a single collector, reaching flow rates 20-30% in excess of the specified 0.026 gpm/tube

(0.1L/tube/min) level is acceptable but, as described above, will reduce the temperature rise and potentially

cause pump cycling.

✖ Damage to collectors due to heat expansion and copper header distortion is not eligible for warranty

claims.

󱚡 WARNING

Apricus Solar Collector Installation & Operation Manual - USA

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