Why modulating technology helps to reduce energy and increase the shelf life of food?

Why modulating
technology helps to
reduce energy and
increase the shelf life of
food?
49. Međunarodni kongres i izložba o KGH, Beograd, 5–7.12.2018
49th International HVAC&R Congress and Exhibition, Belgrade, 5–7 Dec. 2018
1
Marco Galluppi

2
Summary
1. Overview
2. Commercial refrigeration trends
3. Effect of the use of modulating components on semi plug-in units
4. Energy reduction by the use of modulating technology on condensing units
5. Conclusions

3
Summary
1.Overview
5. Conclusions

4
Kigaliamendment
REDUCTION
OF DIRECT
CO2
EMISSIONS
Ecodesign:
Increasing efficiency
REDUCTION
OF INDIRECT
CO2
EMISSIONS
ALTERNATIVE
REFRIGERANTS:
R-744 (CO2)
R-717 (Ammonia)
Hydrocarbons
HFO’s
Minimize
environmental
impacts during
the whole of the
life cycle of the
equipment
F-gas:
Phase-down of HFC’s
NEW DESIGN OF
EQUIPMENT
1. Overview

5
Summary
1. Overview
2.Commercial refrigeration trends
5. Conclusions

6
Semi plug-inunits
Semi plug-in units are self-contained cabinets with water-cooled condensing units, rejecting the
heat of condensation by a water loop, thus avoiding an increase in temperature inside the
supermarket.

7
Semi plug-inunits: advantages
 Less charge of of refrigerant: less
CO2 equivalents in the system
 Ease of installation & maintenance
 Less leaks and lower frequency
of leak checking
 Lower operating and maintenance costs

8
Condensingunits
Condensing unit is a product integrating at least one electrically driven compressor and one condenser,
capable of cooling down and continuously maintaining low or medium temperature inside a refrigerated
appliance or system, using a vapour compression cycle once connected to an evaporator and an
expansion device (Ecodesign Directive, 2009).

9
Condensingunits
The most popular application for condensing units is convenience stores.
Annual electrical energy consumption:
Convenience stores = over 2000 kWh/m² of sales area
Hypermarkets = 700 kWh/m² of sales area
The refrigeration systems account for
between 30% and 60% of the electricity
consumed.
The optimization on the refrigeration system will bring important benefits such as the
reduction of emissions and significant savings on the electricity bill.

10
Modulatingcomponents combinedwithadvancedtechnology
The solutions of semi plug-in units and condensing units can be optimized if equipped with
modulating components combined with advanced control and monitoring systems:
 Advanced electronic controllers
and supervision systems
 DC technology  Electronic expansion valve
Hig he r se aso nale fficie ncy Lo we r pre ssure diffe re nce Easie r to pre ve nt failure s

11
Summary
1. Overview
3.Effect of the use of modulating components
on semi plug-in units
5. Conclusions

12
Objective: compare which are the differences between temperature
and humidity trends in two configurations of semi plug-in units.
Four showcases were used: two operating with modulating technology including DC
compressor(1 and 3), and two operating with the compressor operating in ON-OFF
mode (2 and 4).
Temperature and humidity sensors were placed in three of the seven shelfs as well as
samples of turkey meat in each shelf.
Regulation temperature was set as a weighted average (50-50) of each showcase air
ON (evaporator air inlet) and air OFF temperatures (evaporator air outlet), obtaining a
value of 2.8±0.1 °C foreach cabinet.

13
DC compressor: showcases 1, 3
ON-OFF compressor: showcases 2, 4
DC compressor: constant
temperature (except during
defrost),
ON-OF compressor: the
temperature fluctuates due to
the constant on and off of the
compressor.
The hig he st pe aks re pre se nt
the de fro st o f the cabine ts,
which are the o nly “o ut o f se t
po int” fo r sho wcase s 1 and 3.
Temperaturetrend
The variations in temperature can deteriorate the quality of the food, making it shorterits shelf life.
(Soo Dong, S. et al., 2013)

14
DC compressor: showcases 1, 3
ON-OFF compressor: showcases 2, 4
DC compressor: constant
humidity (except during
defrost),
ON-OF compressor: the
humidity fluctuates due to the
constant on and off of the
compressor.
The hig he st pe aks re pre se nt
the de fro st o f the cabine ts,
which are the o nly “o ut o f se t
po int” fo r sho wcase s 1 and 3.
The effect of humidity on food is very relevant, in some cases even more than the effect of temperature
(Forney, C.F., 2008 ; Lineberry, K.R., 2011)
Humiditytrend

15
0
1
2
3
4
5
6
7
0:00
0:25
0:50
1:15
1:40
2:05
2:30
2:55
3:20
3:45
4:10
4:35
5:00
5:25
5:50
6:15
6:40
7:05
7:30
7:55
8:20
Showcase1-Temperature(°C)
Time (h)
Higher shelf
Middle shelf
Lower shelf
0
1
2
3
4
5
6
7
8
0:00
0:25
0:50
1:15
1:40
2:05
2:30
2:55
3:20
3:45
4:10
4:35
5:00
5:25
5:50
6:15
6:40
7:05
7:30
7:55
8:20
Showcase2-Temperature(°C)
Time (h)
Higher shelf
Middle shelf
Lower shelf
For both the showcases, with and without modulating technology, the lowest temperature was that in the
middle shelf, whereas the highest one corresponded to the highest shelf, obtaining differences of more
than 1.5 °C.
Comparisonbetweentemperaturetrendinhigher, middleandlowershelfs
Showcase2(without modulatingtechnology)Showcase1(withmodulatingtechnology)

16
Summary
1. Overview
4.Energy reduction by the use of modulating
technology on condensing units
5. Conclusions

17
Objective: to study how the combination of the two modulating components, DC
compressors and electronic expansion valves, helps to reduce the energy
consumption of condensing units.
Two different solutions were compared, one with condensing units equipped with DC
compressorand electronic expansion valve, and one with ON-OFF units and
thermostatic valve.
The store consists in 3 medium temperature walk-in coolers with a cooling
capacity of 3.5 kW each one. The data were collected during 4 weeks for each
technology.

18
Energyconsumptionof thecondensingunits
- 28 % of energy
consumption when
using DC compressor
and electronic
expansion valve
Solution Min. T [°C] Max. T
[°C]
Average Tamb
[°C] Energy consumption [kWh]
ON-OFF compressor +
thermostatic valve
22.2 36.7 27.5 2544
DC compressor +
electronic expansion valve
23.2 39.5 31.7 1844

19
Summary
1. Overview
5.Conclusions

20
5. Conclusions
 Semi plug-in cabinets and condensing units are increasingly used as an
alternative to centralized refrigeration systems
 The use of DC compressor on semi plug-in units allows to avoid
fluctuations on the values of temperature and humidity, which have
consequences on the quality of the food
 The use of modulating components such as DC compressor and
electronic expansion valve allowed to save 28 % of energy with respect
to the use of ON-OFF compressor and thermostatic valve

21
marco.galluppi@carel.com
Thank you for your
attention

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