Danfoss Ice machine article User guide

Brand: Danfoss

Model: Ice machine article

Type: User guide

DANFOSS WORKS ENERGY EFFICIENCY

IN ICE CUBE MAKING APPLICATIONS

R E F R I G E R A T I O N A N D

A I R C O N D I T I O N I N G

Ice cube machines are a tough application for a refrigeration circuit as, due to the

freezing cycle and the harvest cycle, temperatures and pressures change several

times every hour. They are among the most energy consuming appliances, as a recent

report of the California Energy Commission shows. Facing this fact, the Appliance

Efﬁ ciency Regulation in North America is setting the rule : all ice cube machine

manufacturers have to increase focus on how to lower energy consumption. The

challenge manufacturers now have to face is to increase ice quantity and quality,

reliability and long lifetime for units, while lowering their energy consumption.

To optimise the systems from a technical and an energetic point of view, efﬁ cient

components adapted to this speciﬁ c application are required.

Ice cube machines require

short cycle times to obtain

their rated ice capacity.

As a consequence, most

ice cube machines are

equipped with superheat

controlled thermostatic

expansion valves, which

inject refrigerant into the

evaporator. Capillary tubes

and ﬁ xed oriﬁ ce expansion

devices, however, cannot

control the superheat through

the entire cycle. The impact

on the system can be very

negative: If the superheat

is too low, liquid may ﬂ ood

back to the compressor and

damage it. If the superheat

is too high, the capacity of

the units decreases and the

energy consumption per kg

of ice increases. Therefore,

the use of an expansion valve

makes the difference : its

performance affects quantity

& energy – you need to select

the best expansion valve for

the application to maximize

performance…

A better regulation for

energy savings

The Danfoss TUB/C expan-

sion valve offers a unique

solution, as it can be specifi-

cally adapted to this applica-

tion characterised by its con-

stantly changing pressures

and temperatures through

the ice freezing cycle and

the hot gas harvest cycle.

Due to their specific proper-

ties, including orifice size,

static superheat setting and

charge composition, TU-

valves ensure stable con-

trol by maintaining the same

low superheat for the entire

evaporating temperature

range during the freezing

cycle (0

°C to –20°C), and by

remaining closed during the

harvest cycle (hot gas).

To achieve such high preci-

sion, the valves must be

totally uniform. Small devia-

tions in the capacity or the

superheat setting are not

acceptable, as they might

influence the stability of the

operating conditions. Due

to fully automated manu-

facturing processes, reg-

ular and comprehensive

quality checks, as well

as long-term experience,

Danfoss is able to guaran-

tee the highest perform-

ance for TU-valves within

extremely small toleranc-

es of charges, superheat

settings, etc.

TU-valves are made of

stainless steel and offer the

advantage of a laser-

weld-

ed diaphragm and capillary

tube. This leads to optimum

strength and, as a conse-

quence, to a longer lifetime,

which is extremely impor-

tant in ice cube machines

with their high number of

cycles.

Long lifetime and reliability

are key words for ice mak-

ing machine manufacturers

entailing less maintenance

requirements and, at the

end of the day, savings in

their service and warran-

ty obligations towards their

customers.

performance tests are done

at Ta/Tw

°C conditions, i.e.

38°C/32°C – 21°C/10°C.

To carry out the tests, the

ice machines are equipped

with extensive measurement

devices such as DIN IEC

class B Temperature PT1000

sensors (+/-0,3K), AKS32

pressure transducers (+/-

0,3%) as well as further

equipment to control energy

consumption and power and

to collect the data.

On the individual ice cube

machines, baseline tests

are carried out at the

rating conditions. Then the

individual components one

A full range for a better

regulation

Obviously, TUC expan-

sion valves are not the

only components with an

impact on the energy effi-

ciency of ice machines.

Danfoss offers, as well :

- ice machine optimised

compressors that provide

overall system efficiency

improvements

- small and tight EVU sole-

noid valves for low energy

consumption at hotgas

harvest and increased ice

production

- filter driers type DML

with a high filtration rate

and moisture absorption.

These tests and practical

experiences in the field

have given Danfoss an in-

depth understanding of

the ice machine applica-

tion for the benefits of

manufacturers.

Fully equipped test

chambers to support

ice making machines

manufacturers

As for Danfoss, they have

decided to support ice

machine manufactur-

ers with their tests. They

equipped a test chamber at

their headquarters’ laborato-

ry to do full scale tests of ice

machines according to the

required ARI standard 810

“Automatic Commercial Ice-

Makers” and in accordance

with ANSI/ASHRAE Standard

29 “Methods of Testing

Automatic Ice-Makers”. The

certification program ratings

are verified empirically at

standard rating conditions,

i.e. an ambient temperature

of 32.2

°C, a portable water

inlet temperature of 21

°C

and a water inlet pressure

of 30 psig / 2.1 bar. The

test mainly focuses on the

ice harvest rate, portable

water use rate and electrical

energy consumption. Further

by one are replaced with

Danfoss energy enhanced

components and the tests

will be repeated. This step

by step analysis allows the

ice machine manufacturer

to determine the optimal

combination of components

for their machine design,

maximixing performance

while reducing energy.

ITSC.PA.ART.01.02 May 05 - Produced by Danfoss

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice. This also applies to products

already on

order provided that such alterations can be made without subsequential changes being necessary in speciﬁ cations already agreed. All trademarks in this material are property of the respective

Danfoss Ice machine article User guide

Danfoss Ice machine article User guide

Danfoss Ice machine article User guide

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