Boreal ACDX-45, Руководство по установке

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2005 Boreal Geothermal Inc. www.boreal-geothermal.com
7. Place the thermostat function selector in the COOL posi-
tion. Placing the selector in this position energizes the
reversing valve and loop 1 solenoid valves. Next turn
down the stat to a temperature that will cause the
air-conditioning to begin. The blower and compressor
should operate. The outlet temperature will be approx.
15° to 25° F. cooler than the return air temp.
General Maintenance
As with any piece of equipment there will eventually be
some maintenance to be done on the heat pump however a
ACDX heat pump is relatively maintenance free and only one
item will need attention as follows:
•
Change the air filter when required.
Theory of Operation
The ACDX heat pump utilizes a typical vapor compres-
sion refrigeration cycle similar to many other common appli-
ances. The only difference between a Direct Expansion heat
pump and a conventional geothermal unit is the fact that the
BOREAL® unit has it’s heat exchanger embedded in the
ground.
Due to some engineering obstacles involved with remote
parallel evaporators some special equipment and techniques
which are described below are required to allow such a sys-
tem to work effectively.
4 - Ton System Description Heating Mode
All BOREAL® ACDX systems utilize multiple earth
loops to transfer heat to and from the ground. One loop per
ton of capacity is normally required and during the heating
mode all the loops are active.
Liquid refrigerant passes from the air handler section
through the bi-flow filter-drier and through the cooling TX
valve which is fully open by virtue of it’s equalizer line being
connected to the common suction inlet line and it’s controller
bulb attached to the vapor inlet line (hot in heating mode) of
the air handler. Liquid refrigerant then travels towards the
liquid line header, solenoid valve and check valve assembly.
Solenoid valve “A” is a normally open valve and is de-
energized during the heating mode thus refrigerant can travel
unrestricted through the heating check valves (B,C,D,E) to-
wards the inlet of all the heating TX valves.
Each heating TX valve is equipped with a small bypass
capillary tube which allows approximately 1/2 ton of refriger-
ant to flow regardless of the position of the TX valve. This
by-pass is intended to perform 2 functions:
♦
Limits the amount of hunting done by the TX valve due
to the long evaporator length.
♦
Prevents the heat pump from tripping out on a high pres-
sure limit if all the heating TX valves decide to close at
the same time.
The TX valves control the flow of liquid refrigerant to it’s
loop by virtue of the sensing bulbs being attached to each
respective return vapor line and all the equalizer lines con-
nected to the common suction inlet line. The sensing bulb of
each TX valve is located just below the connection to the 3-
way valves on the gas line header assembly.
The liquid refrigerant coming in contact with the warm
earth vaporizes to a gas and flows back to the heat pump via
the 1/2” OD copper return vapor lines. System oil is entrained
in by the velocity of the return gas and is continuously swept
back towards the compressor. Refrigerant vapor normally
picks up from 5° to 12°F superheat as it returns to the heat
pump. Refrigerant vapor enters the 3-way valve header as-
sembly at ports “F”, passes straight through the valve to ports
“G” where it exits to the vapor line header. From the vapor
line header the refrigerant gas enters the reversing valve at
point “H” and exits to the common suction line “I” where it
travels to the accumulator and onward to the compressor. Hot,
high pressure refrigerant gas enters the desuperheater coil, on
units so equipped, where a small portion of its heat is re-
moved in the production of hot water. The hot refrigerant then
enters the air coil where the refrigerant vapor is condensed by
the process of cool household air flowing across the air-to-
refrigerant coil. Further sub-cooling of the refrigerant liquid
takes place as the refrigerant reaches the bottom of the coil
and begins another cycle.
General Operation - Cooling Mode
During the cooling mode of operation the BOREAL®
ACDX heat pump takes control of the earth condenser coils
and allows the most efficient transfer of heat to the ground via
an onboard computer which monitors the conditions under
which the heat pump is operating and stages the earth loops
into the system as required.
When the heat pump thermostat signals for cooling three
items are energized:
•
The reversing valve.
•
The liquid line solenoid valve.
•
One or more of the vapor line 3-way valves.
Refrigerant is directed to one or more loops based on loop
temperature and stored information in the embedded control-
ler. Each of the loops can be used independently or in con-
junction with one or more of the others. The controller makes
decisions based on preset information concerning system ca-
pacity, horizontal or vertical configuration, amount of heating
and cooling runtime, etc.
Refrigerant leaves the compressor and enters the desuperhea-
ter coil as in the heating mode which removes a small portion
of the heat available to make hot water. The gas then flows to
the reversing valve and onwards towards the refrigerant vapor
header. The 3-way valves which are powered “ON” by the
controller board, allow refrigerant to flow into the earthloops
to which they are attached. Valves which are deenergized