Cli-mate CLI-AP30 Especificações descarregar pdf (Página 25)

use with it (without corrosion). Contact the expansion tank manufacturer to confirm which model is

necessary, given the system fluid type, fluid volume, pressure and operating temperature range. Heat

transfer fluids, such as propylene glycol have a higher expansion coefficient than water, but given the small

volume of fluid in most residential closed loops (domestic system only, max 60 tubes) the standard Apricus

expansion tank is adequate.

d) Steam Formation: When steam forms, the volume it occupies is much greater than water. At

atmospheric pressure, 1 gallon of water can expand to occupy 223 ft

(1L of water = 1.673 m

). Under

pressure, steam can be compressed into a much smaller space. At 50 psi, a common operating pressure

for the collector during a period of stagnation, the volume that steam would occupy is around half its volume

at atmospheric pressure (around 104 ft

per gallon (0.885 m

per Liter).

In the solar collector, when the fluid temperature exceeds about 290

F (145

C) water (or water in a glycol

mix) will form steam in the header. The entire fluid contents of the header, DO NOT form steam, which

would result in nearly 10.5 G (40 L) of additional volume, far beyond the capacity of the expansion tank.

Instead, the capacity of the header and pipe in very close proximity fill with steam, an expansion volume of

about 0.26 G (1 L) per AP-30 collector. Only a very small volume of water is actually turning to steam,

about 0.067 fl.oz (2 ml). This steam will quickly clear the header of fluid by pushing the fluid down the return

line, since there is a check valve in or after the pump on the Supply (Feed) Line. The standard 4.7G

expansion tank provided with the closed loop pump station or a similarly-sized expansion tank on a direct

flow system will be able to accept this volume.

3.12. Heat Exchangers

3.12.1. Internal Coil Heat Exchangers

a) Coil Design: See the Apricus Schematics and Parts List that notes the correct tank with internal coil heat

exchanger designed specifically for solar systems. The approved tank(s) are listed for each system in the

Schematics and Parts Lists Document.

b) Closed Loop Fluid Volume: When calculating the closed loop fluid volume, remember to include the

volume in the coil, which should be listed on the tank’s product specification sheet.

3.12.2. Brazed Plate Heat Exchangers

a) Advantages: Brazed plate heat exchangers (BPHE) are a compact and efficient heat transfer unit ideal

for use in solar thermal systems. They are superior to coil heat exchangers because they allow the solar

collector to run at a lower, more efficient temperature, while transferring the same amount heat energy to

the tank.

b) Disadvantages: BPHE require an additional pump to facilitate circulation on the potable (end-use) side

of the plates. In areas with hard water, limescale can build up restricting flow and requiring periodic

flushing.

c) Dual Wall: BPHE are dual wall models. Apricus OG-300 systems are only available with dual wall

brazed plate heat exchangers with leak detection.

󱚡 WARNING

Selecting the proper heat exchanger is important for the safety of the system. You may only

use a single wall heat exchanger (internal or external) if the heat transfer ﬂuid being used is

Generally Regarded As Safe as approved by the FDA. This information can be found in the

Material Data Safety Sheet of the ﬂuid (Appendices 10-17).

3.13. Wind Loading

a) Collector wind loading must be considered and the resulting stress on attachment points thoroughly

examined. The attachment method may need the stamp of a professional engineer, depending on local

Apricus Solar Collector Installation & Operation Manual - USA

1 2 ... 20 21 22 23 24 25 26 27 28 29 30 ... 119 120

Comentários a estes Manuais

Sem comentários

Cli-mate CLI-AP30 Especificações Página 25

Comentários a estes Manuais