Category: Technical information associated with Sanyo Gas Heat Pumps
Technical Background
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Sanyo Air Conditioners Gas Heat Pumps - Technical Background
GHP Gas Hear Pumps Technical Background:
SANYO’s experience in GHP technology gives them a clear advantage in
a market that demands diversification. They are the GHP leaders in Japan
with 38.6% market share, where gas powered air conditioning constitutes
44% of the market. In fact Japan is the birthplace of GHP, where it was
developed in the early ‘eighties when the demands of Tokyo’s 20-million
population meant the national grid threatened to reach breaking point.
The Japanese government invited SANYO to help develop an alternative to
electrically powered air conditioning and the result was the first ever
Gas Heat Pump in 1985. Followed by the only 3 pipe VRF in 2005, and now
the ECO G Power in 2008.
GHP – The Facts:
The operating temperature conditions are -20ºC for heating and -10ºC
for cooling. No defrost operation is required in the heating mode.
Therefore no heating ‘downtime’. Power supply for the GHP is 20A single
phase for all models, electrical consumption due to inverters is as low
as 0.63 kw. Either natural mains gas or LPG can be used to power the
system. All GHP pipe work and communication wiring are as per the SANYO
ECO Multi VRF system, allowing the mixing of GHP & ECO on the same
“S-Net” configuration. (Communication BUS) The system installation
procedure is identical to the current ECO Multi VRF system, although the
permitted indoor unit per outdoor unit quantity is increased to a
maximum of 32, which applies to all models. The recommended indoor to
outdoor capacity ratio is from 50% all the way up to 200%, offering
greater flexibility to users.
All GHP models use Nissan built engines and refrigeration compressors
produced by Japan based Seiko Industries. There are two engine
capacities used. The 1300cc twin overhead cam is used for the 8 and
10hp, which requires one compressor while the 2500cc overhead valve
engine is installed to the 13, 16, 20hp and 25hp, which has twin
compressors fitted. The 8 and 10hp model includes one condenser fan
while the 13, 16, 20hp and 25hp uses two fans. The condenser fan motors
are single-phase inverter, driven using DC voltage. The inverter system
also controls the single-phase coolant water pump. Waste gas output is
minimised in the GHP with the aid of an acid neutralizer, fitted to the
engine exhaust system. With regular servicing, the engines offer
approximately 13 years hassle free operation. The service requirements
of the outdoor units are minimal. Major servicing is suggested at 10,000
running hour intervals. This tends to work out at an average of one
service every four years. With 8,800 hours in a full year, even if you
run the unit full time servicing would only be required once a year. The
facility for Refrigerant Leak Detection is in-built into the GHP just as
on the three pipe electrical ECO version. An external refrigerant
detector is connected to the CN6 plug on the indoor unit PCB. If the
sensor is activated then the system immediately shuts down. A dedicated
P14 fault code is then displayed on the system remote controllers.
GHP Outdoor Units - Engine Components:
To achieve long service intervals offered by the GHP its engine
requires an oil reserve. Up to 50 litres of oil are stored in a single
oil tanks. The oil system has an external oil pump to circulate the oil
from the oil tank to the engine sump. The engine also has an internal
oil pump as per a normal car engine. Two Air Cooled Water Coolant heat
exchangers are positioned before the refrigerant Air Cooled Heat
Exchangers, which are of equal size. If the engine water rises above
80ºC then coolant water passes through these. There are two Coolant
Water tanks installed. The main tank is installed at high level and the
reserve tank is installed below. The coolant water is filled with
water/glycol to prevent freezing as low as -45ºC. The system’s Coolant
Water Pump is an Inverter driven pump, operating on 240DC voltage full
speed = 3200RPM. Its Air Intake Filter is very similar to that found in
a car engine.
The GHP uses a special type of spark plug designed for longer life. The
same plug is used for all models. Control of the Gas/Air Mixture control
valve or Throttle valve is achieved by a step motor operating between
0-480 steps. The control valve can be varied as and when more engine RPM
is required. The GHP’s Exhaust/Coolant water heat exchanger is of the
Shell and Tube variety, acting as a Condenser to condense the moisture
from the exhaust gases. Its Exhaust Gas Drain Neutralizer ensures that
the moisture condensed from the exhaust gases is passed to the Drain
Neutralizer. Within the Neutralizer there are Calcium Carbonate
chippings that absorb any acid produced, maintaining the drain water at
a ph level 6.8-7.0. The Stainless Steel Exhaust Muffler normally
operates at 80ºC. A high temperature muffler sensor is fitted to ensure
that if temperature exceeds 130ºC then the high temperature alarm will
be triggered. A gas control valve in the system incorporates three jets:
a fixed main jet, a fixed by-pass jet and a variable control jet. The
valve also contains an adjustment plate that is used if the GHP is run
on LPG.
GHP Refrigeration System:
The compressor used in the refrigeration system is a Belt driven
Multi-Vane Rotary compressor incorporating five Vanes, two Suction and
two Discharge ports. The lubrication oil used is a Poly Alkaline type
unique to the GHP. The 8 and 10hp model contains a single compressor
with on/off magnetic clutch control.
The 13, 16, 20 and 25hp (2 and 3 pipe) models, feature a twin compressor
arrangement, one with on/off control and one at a constant operation.
Its Oil Separator is the same as the Eco-Multi, as is its Four Way
Reversing Valve. The Condenser fan motor is a 240V DC Inverter driven
type. The 8 and 10hp has a single fan while the 13, 16, 20 and 25hp
contains two fans, which are both inverter driven. Two outdoor heat
exchangers are incorporated in the refrigeration system, both equal in
size similar to the ECOi System. The Suction/Coolant Water Heat
Exchanger used in the system is a Plate type Suction Gas/Coolant Water
Heat exchanger that is used in the Heating mode. Coolant water is passed
through the exchanger to allow Suction gas to absorb heat transferred
from the engine. The water flow is regulated via a 3 Way control valve.
A Hot Gas Bypass Valve is in place to unload the compressor at starting.
It is also used to prevent low-pressure gas situations occurring. Two
standard Pressure Transducers are fitted, one to the Discharge gas line
for high pressure control and one to the Suction line. These sensors
enable the actual operating pressures to be viewed via the outdoor PCB.
General Mode of Operation:
Engine Operation:
When there is a requirement for ‘Thermo-On’ from a single fan coil
(the minimum size is 2.2 kw) or multiple fan coils, then the engine is
started. At this point the engine RPM is governed by the difference
between the temperature set point and actual current operating
temperature. Therefore the greater the temperature difference, the
higher the engine RPM. The minimum operating engine RPM is 800 and the
maximum RPM is 2200. If all indoor units are at ‘Thermo-off’ then the
engine stops. The engine has been designed to operate within 10,000 hour
service intervals. The engines are expected to use oil at a rate of
3cl/h.
Additional Features:
Water Chiller:
To increase the flexibility and usage of the GHP, a water chiller can
be installed. The chiller is available in two sizes offering cooling
capacities of 25 kw and 50 kw. The chiller can be positioned up to 120
metres from the outdoor unit, therefore internal chiller location is
made possible. The operating water range for the chiller is +5ºC to
+15ºC as standard. If required the temperature range can be altered to
offer low temperature usage from -15ºC to +5ºC albeit anti-freeze
additives are required for the water system. Simple local control at the
water chiller is a standard feature. Also a remote control option is
available, allowing remote stop/start and alarm capabilities.
Internal Hot Water Heat Exchanger:
The 13-25hp GHP outdoor units are fitted with an internal additional
heat exchanger. This allows for external hot water to be obtained
whenever the GHP unit operates in the cooling cycle. Instead of
dissipating the engine heat to the atmosphere, the engine cooling water
is passed through the internal heat exchanger and this heat is then
passed into a secondary water system. Up to 22 kw of heat can be
produced at 75ºC making this option a viable means to boost any hot
water system.
Commissioning:
To make commissioning as hassle-free as possible all GHP outdoor
units after final production are passed to the test run bay for a
minimum one hour trial run. Extensive testing and operation checks are
carried out. Only after passing all the stringent testing are the GHP
systems passed for export. Site commissioning for the GHP is similar to
the electric ECO Multi VRF system. After completing all field wiring and
piping, the GHP utilises a simple ‘Automatic Address’ procedure for the
indoor and outdoor units (no need for any DIP switch settings) which
allows for quick system set-up. On completion of the ‘Auto Address’
procedure system operation is now possible. Operation of the GHP is then
monitored, ensuring all run conditions are within normal operating
parameters. To assist in collating the run information, the SANYO
service checker can be connected. After recording the running conditions
this information can then be stored and printed for insertion into the
commissioning documentation. With SANYO offering to commission all GHP
systems and offer the relevant gas certification and subsequent
maintenance training on-site, any concerns arising from this new
technology are instantly dealt with.
Service/Maintenance Requirement:
The following are required when carrying out a 10,000hr service.
1) Change all oil
2) Change oil filter and oil blow by filter (only installed on 8 &10hp)
3) Change Air Intake filter
4) Change spark plugs
5) Clean Drain Neutralizer crystals
6) Engine inspection including compressor drive belt.
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Sanyo Air Conditioners
ECOi House
9 Whyteleafe Business Village
Whyteleafe
Surrey
CR3 0AT
Tel: 0845 6126364
Fax: 0845 6126365 |