21/11/2016
Daikin focuses on energy efficiency
This article on Daikin’s approach to new container
refrigerants was originally published in the August 2016
edition of World Cargo News and is reproduced here with
kind permission of the publishers.
Japan-based Daikin is facing the challenge of finding low
GWP (global warming potential) refrigerants across a wide
range of markets and industries. In re**er containers, the
company believes that “to find a solution with a further low
GWP, Daikin thinks that the safe usage of mildly flammable
refrigerants is essential.” Daikin is now proceeding with a
risk assessment of mildly flammable refrigerants in re**er
operation, and R&D work on the development of practical
protection devices has also begun. “At the same time, Daikin
is applying alternative refrigerant candidates to the platform,
based on the current machine and evaluating the COP
[coefficient of performance] and cooling capacity under each
condition,” the company added.
Daikin makes it very clear that in pursing mildly flammable
refrigerants it is not rejecting CO2 as a refrigerant for re**ers
– something it has never done and does not intend to do in
the future. The company has experience with CO2 through its
air conditioning business. “However, when we think of it as
an alternative refrigerant for re**ers, it would be difficult for it
to maintain the ease of handling and same performance as
the current machine. This is because CO2 has high pressure,
and therefore specific tools will be needed for handling and
maintenance in the field,” Daikin explained.
The company is also concerned about the performance of
CO2 at highambient temperatures. “The specific feature
of CO2 is not being energy efficient at a high ambient
temperature (above 30 ºC), which is highly disadvantageous
towards re**ers because often their routes involve going
through areas of high ambient temperature, such as crossing
the equator. Furthermore, it is essential to look in to energy
efficiency when considering the impact it has on global
warming, which means that, ultimately, CO2 refrigerants will
not give a positive impact to the environment, when used on
re**er equipment,” the company added.
Re**er requirements
Daikin serves many different markets, and it notes that
CO2 is gaining traction in supermarket refrigeration in some
countries, though not yet on a global scale. There are other
applications where it considers CO2 may be the most
appropriate refrigerant, including permanent facilities where
the system can be designed for the expected heat load, and
service personnel can be appropriately trained. The company
cautions, however, that “just because a CO2 refrigerant is
gaining traction in one market does not mean that it can
be applied to re**ers as well”. Different factors have to be
considered when evaluating the best alternative refrigerant
for stationary use, compared to a mobile application such as
a re**er. “For example, since re**ers travel all over the world,
maintenance needs to be available anywhere and anytime,
even on board,” said Daikin.
A unified approach
Daikin has heard the call from re**er owners and operators
for the industry to find a unified alternative refrigerant, which it
says is something the company supports. However, in reality,
there can be no ‘one size fits all’ refrigerant, as the different
operators do not have common requirements regarding
safety, energy efficiency or cooling capacity. There being
no single requirement, a supplier like Daikin has to find the
best balance, considering the different weighting that re**er
owners give to the four core factors: safety, environment,
energy efficiency and cost.
“The requirement of reducing environmental load is seen as
important, not only from shipping lines, and Daikin agrees
to put it as its first priority,” the company stated. “However,
Daikin believes that it is not only GWP that gives an impact on
environmental load, but the refrigerants which have the best
balance of energy efficiency, cost effectiveness and safety
contribute to the environment the most, and are also the
ones to correspond to the customer’s need. Therefore, Daikin
considers R1234yf, R513A/B and R32 as the most ideal
candidates for re**ers at the moment.”
As has been noted previously, Daikin considers R32, which
has a GWP of 675, and HFO gases to offer one of the best
answers to the container refrigerant dilemma, following the
development work the company has already carried out in
the air-conditioning field. Daikin has air conditioners with
R32 available in over 48 countries, as of March 2016. The
first product was launched in 2012, and it believes HFO
single/blend (R1234yf, R513A/B) and R32 would produce
a refrigerant better suited to re**er box operation, where
internal temperatures may vary between -30 ºC to +30 ºC and
ambient temperatures range from -30 ºC to +50 ºC. R1234yf
is particularly promising on the GWP front, with a GWP of
4. With R513A/B or R32, it would be possible to achieve a
70% reduction in the GWP of R134a while being more energy
efficient.
Energy efficiency, Daikin stresses, should not be overlooked
in favour of finding a lower GWP. Power consumption of a
re**er unit has a greater impact on the environment than
other refrigeration applications because re**ers are powered
by vessel generators while they are at sea. “Electric supply
is provided by combusting fossil fuels, and, therefore,
energy conservation links directly to the reduction of CO2
emission. This is why Daikin thinks having an energy efficient
unit on board of the vessel will be important,” the company
concluded.
source: www.worldcargonews.com
