Mitsubishi Heavy Industries Technical Review Vol. 56 No. 4 (December 2019)
1Generator-driven Type Transportation Refrigeration
Heat-Pump Unit for Trailers

Distributor
M i ts u b i s h i H e a v y I n d u s t r i e s T h e r m a l
Tr a n s p o r t E u r o p e G m b H

Along with global initiatives to reduce environmental impact, the implementation of suchmeasures is also being promoted in the logistics industry. In terms of transportation refrigeration
units, there is a strong need to reduce CO2 emissions through efforts such as improved
energy-saving features and lowering the noise level during operation/transport in urban areas or atnight. In response to such demands for lower environmental impact, Mitsubishi Heavy Industries
Thermal Systems, Ltd. has developed the TFV150GA transportation refrigeration unit for trailers
with a generator-driven heat pump, to make both silent operation and energy conservation
simultaneously possible.

|1. Product outline
A “generator-driven system” in which the refrigeration unit engine is equipped with agenerator has been adopted. By operating the engine at a low rotation speed and using an inverterto control our proprietary hermetic 3D scroll compressor, we have realized refrigeration operationthat is powerful yet silent. Through the use of a heat pump cycle system, heating performance andfuel economy have been markedly improved.

|2. Product features
2.1(1)

Lower environmental impact
Substantial noise reduction from the existing model
The biggest external source of noise is the refrigeration unit engine. To realize silent
operation, the refrigeration unit engine is run at constant low rotation speed and the engine isenclosed in a soundproof structure that also enables proper engine intake and heat dissipation totake place (Figure 1). For the external fan (which is the next biggest source of noise), a scimitar
propeller fan with serrations with a proven record of use in air conditioners has been adopted. A
four-pole AC motor is used to operate it at a low speed to reduce the noise level (Figure 1).
With these features, the noise level has fallen by 9 dB(A) from our existing model, realizing thelowest noise level in the industry.
With inverter control, the refrigeration capacity can be adjusted by freely changing thenumber of compressor revolutions despite the engine rotating at a constant speed. Thus, “silent”
yet “powerful” operation has been realized, something that was not possible with conventionalmodels because the compressor contained therein was connected to the engine by a belt. Evenin urban areas sensitive to noise pollution, therefore, deliveries can be made while operating inalways-silent mode. This reduces the burden on drivers who otherwise have to select thedelivery route carefully.

Mitsubishi Heavy Industries Technical Review 56 No. 4 (December 2019)
2Figure 1

Actual example to reduce the noise level(2)Improved energy-saving performance
The inverter is used to control the number of compressor revolutions in such a way as toalways enable the refrigeration unit to operate with high efficiency in terms of energy
consumption (Figure 2). The use of the heat pump cycle system has improved the heating
operation efficiency. Together with the refrigerating/heating capacity controllable by theinverter, the state-of-charge monitoring of the lead storage battery for engine start-up
eliminated the need for uneconomical engine operations such as idling for charging whencooling is not needed (Figure 3), thus decreasing the engine operating rate. As a result, a
substantial reduction in the actual annual fuel consumption (-25% from that of the existingmodel) has been realized.
(3) Adoption of a refrigerant with lower environmental impact
By adopting R410A, the global warming potential (GWP) of the refrigerant has been
reduced to 2090 from the GWP (3920) of the R404A refrigerant currently used in manytransportation refrigeration units. This represents a 47% reduction, thereby helping to mitigate
global warming.
(4) Use of European standard Stage V engine
From 2019, the European Stage V emission regulation (EU Stage V) standards for
non-road diesel engines are in effect. The engine installed in our transportation refrigeration
unit is compliant with these standards and is therefore environmentally sound. By restraining
NOx and PM emissions, it contributes to preventing the expansion of air pollution.

Figure 2 Control map for the number of revolutions at
the highest efficiency

Mitsubishi Heavy Industries Technical Review 56 No. 4 (December 2019)
3Figure 3 How to reduce the engine operation rate by eliminating the need for idling
operation(5)2.2Lightweight refrigeration unit
With fewer parts and a simplified frame structure to which the parts are fitted, thistransportation refrigeration unit is 110 kg lighter than our existing model. The consequent
increase in the load carrying capacity and the improved logistics efficiency lead to lower
logistics costs and reduced CO2 emissions.

Markedly enhanced heating capacity

By adopting a heat pump cycle system with a long, proven record of use in our airconditioners, we have succeeded in markedly improving the heating capacity. This system enables
not only quick heating, but also heat exchanger defrosting within a considerably shortened periodof time even during refrigerating operation, thereby contributing greatly to the improvement ofrefrigerating operation efficiency.

2.3

Better visibility and operability

Because of where the refrigeration unit is installed in the trailer, the controller is locatedabove the driver’s eye level and is therefore designed to have a screen tilted downward at thebottom. The full-dot liquid-crystal display that is used can display information such as the internal
temperature of the trailer in a large text size, resulting in considerably improved visibility. Function
keys are attached below the display, which enables intuitive operation with fewer manipulations.
There is also a presetting function by which four different set temperatures can be saved, thereby
making it easier for the driver to manipulate the controller (Figure 4).

2.4

Solution for vehicle electrification application

By making all the components (e.g., compressor and fan motor) electrically-driven andbuilding a system that can be controlled electrically by the inverter, we have realized atransportation refrigeration unit that is suitable for use in hybrid/electric trailers or regenerative
power supply systems (Figure 5).

Mitsubishi Heavy Industries Technical Review 56 No. 4 (December 2019)
4Figure 4Better controller visibility and operability

Figure 5

TFV150GA power block diagram with three-phase AC 400 V as a power source|3. Specifications and configuration
Table 1 shows the specifications of the TFV150GA, while Figure 6 illustrates theconfiguration.
Table 1 TFV 150GA specifications
Model
Temperature range Internal temperature of the trailerof use
External air temperatureEngine-driven
External:
Commercial
30°C/Internal: 0°Cpower-driven
Refrigeration
capacityEngine-driven
External:
Commercial
30°C/Internal: -20°C
power-driven
Engine-driven
External:
Commercial-10°C/Internal: 12°C
power-driven
Heating capacity
Engine-driven
External:
Commercial-20°C/Internal: 12°C
power-driven
Refrigerant
External
External dimensions(width × height × depth)Internal
Weight (excluding the lead storage battery)°C°C
W

TFV150GA-30 to +30-20 to +40
14,600W

14,700

W

8,080

W

8,090

W

17,100W

15,900W

12,000W

12,100kg
mmmmkgR410A, 5.7 kg
2000 × 2216 × 430
1680 × 1150 × 100770

Mitsubishi Heavy Industries Technical Review 56 No. 4 (December 2019)
5Figure 6

System configuration diagram of the TFV150GA refrigeration unit

Conventionally, when a commercial power supply was used, the capacity of the refrigeration
unit was several dozen percent lower than the case of engine power supply. However, by enabling
the inverter to freely control the number of compressor revolutions in either power supply system,
the refrigeration unit capacities of these two power supplies have become comparable to each other.
The external dimensions are in accordance with the prescribed European trailer dimensions(Directive 96/53/EC) for acceptance in the European market.

|4. Future development
While improving the performance of electric transportation refrigeration units, we will also
take up the challenge of collaboration and the expansion of our product line-up to be responsive toglobal trends of vehicle electrification such as hybrid/electric trailers and regenerative power
supply systems. We look to improve people’s lives by lowering environmental impact in the cold
chain, reducing the burden on drivers and enhancing the quality of transportation.