Energy cost saving evaluation of VSD installation in compressor rack of refrigeration system for the retail and wholesale building

Energy cost saving evaluation of VSD installation in compressor rack of refrigeration system for the retail and wholesale building

ScienceDirect Energy Procedia 00 (2017) 000–000 Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available ScienceDirect Scienc...

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ScienceDirect Energy Procedia 00 (2017) 000–000

Availableonline onlineatatwww.sciencedirect.com www.sciencedirect.com Available

ScienceDirect ScienceDirect

www.elsevier.com/locate/procedia

EnergyProcedia Procedia00 138 (2017) 8–13 Energy (2017) 000–000 www.elsevier.com/locate/procedia

2017 International Conference on Alternative Energy in Developing Countries and Emerging Economies 2017 AEDCEE, 25-26 May 2017, Bangkok, Thailand

The saving 15th International Symposium on District Heating andin Cooling Energy cost evaluation of VSD installation compressor rack of refrigeration Assessing the feasibility of using thesystem heat demand-outdoor for the for retail and wholesale building temperature function a long-term district heat demand forecast

I. Andrića,b,c*, A. Pinaa, P. Ferrãoa, J. Fournierb., B. Lacarrièrec, O. Le Correc

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Anan Watcharapongvinij1*, Apichit Therdyothin1 IN+ 1 Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal Division of Energy Management Technology, School of Daniel, Energy, Environment b Veolia Recherche & Innovation, 291 Avenue Dreyfous 78520 Limay, France and Materials, c Département Systèmes Énergétiques et Environnement - IMT 4 rue Alfred Kastler, 44300 Nantes, France King Mongkut’s University ofAtlantique, Technology Thonburi, 126 Pracha-Uthit Road, Bang Mod, Thung khru, Bangkok 10140, Thailand

Abstract Abstract District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from portion the building sector.consumption These systems high investments which are returned through the heat Buildings generate the highest of energy in require most countries. It includes major contribution in climate sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, change. Therefore, energy conservation in building is important to get higher energy standard of the country. In most regions of prolonging the investment return period. the world, heating and cooling loads represent the largest building-sector energy end-use. This research focuses on an evaluation maininstallation scope of this is to assess the feasibility of using heat demand – outdoor function forthe heatexisting demand ofThe VSD in paper refrigeration system for the retail andthe wholesale building. The temperature total building area of experiential sitedistrict is 10,000 sq.m. withlocated 7,000 sq.m. sale area. The research dataasisaderived from The actualdistrict energyisconsumption forecast. The of Alvalade, in Lisbon (Portugal), was used case study. consisted of and 665 actual load that measurement. Theconstruction method is period comparison between conventional compressor compressor in refrigeration buildings vary in both and typology. Three weather scenarios and (low,VSD medium, high) and three district system. We finally findwere that the energy of VSD compressor wasdeep). not saved for the whole day. The compressor with VSD is more renovation scenarios developed (shallow, intermediate, To estimate the error, obtained heat demand values were efficient than theresults one without compressor during day time. The compressor VSD worked at authors. night or no load, whereas compared with from a VSD dynamic heat demand model, previously developed with and validated by the the without stopped at nightchange or no load. If we would to get saving VSD installation Thecompressor results showed thatVSD when only weather is considered, thelike margin ofenergy error could beefficiency acceptablefrom for some applications . in(the compressor rack, VSD system to set additional to turn off at night or turn off at no load demand error in annual demand wasneed lower than 20% forfunction all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). © 2017 The Authors. Published by Elsevier Ltd. ©The 2017 The of Authors. Published by Elsevier on Ltd. value slope coefficient increased within the 2017 rangeInternational of 3.8% upConference to 8% per on decade, that corresponds Peer-review under responsibility of the scientificaverage committee of the Alternative Energy in to the Peer-review under responsibility of the Organizing Committee of 2017 AEDCEE. decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and ­Developing Countries and Emerging Economies. renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the Keywords: Variable Speed Drive, VSDsuggested for refrigeration VSD compressor coupled scenarios). The values couldsystem, be used to ofmodify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. © 2017 The Authors. Published by Elsevier Ltd. * Corresponding author. Tel.: +0-084-137-1100; fax: +6-602-734-2140. Peer-review responsibility of the Scientific Committee of The 15th International Symposium on District Heating and E-mail address:under [email protected] Cooling. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Keywords: Heat demand; Forecast; Climate change Peer-review under responsibility of the Organizing Committee of 2017 AEDCEE.

1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the scientific committee of the 2017 International Conference on Alternative Energy in ­Developing Countries and Emerging Economies. 10.1016/j.egypro.2017.10.036

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1. Introduction Building energy efficiency is the key to achieve energy conservation and reducing greenhouse gas emissions. The retail and wholesale building sector has been identified. Energy demand and consumption in this sector should be considered to improve efficiency. Refrigeration system in this building sector should be considered to manage and reduce energy consumption. It is operated 24 hour for sale area refrigerator and cold room in the stock area. This research expects to verify VSD in compressor rack in refrigeration system. VSD is a tool to minimize energy for compressor. It’s also prove efficiency of conventional multi set compressor rack and additional VSD in this system. 2. Material and methods 2.1. Objective This research objective is to find out Energy cost saving evaluation of VSD installation in compressor rack of refrigeration system for the retail and wholesale building. The evaluation is a comparison between conventional multi set rack and additional VSD in the rack of refrigeration system. 2.2. Scope of research The case study building for experimental research is retail and wholesale building in Bangkok, Thailand. Building area is 10,000 sq.m. Sale area is 7,000 sq.m. The data parameter comparison is actual consumption and energy cost comparison. 2.3. Research Methodology An experimental research is designed to know actual operation and consumption of both compressor rack between conventional multi set rack and additional VSD in the same system. 2.3.1 Experimental method. This research is an experimental real condition and actual measurement. This system has controller to record performance data but it cannot record energy consumption (kWh) by each compressor. This research is set to know efficiency of each compressor by kWh meter addition in each compressor. Four compressor 56.36 kW in multi set rack are set to be 2 conditions. First condition is conventional compressor rack, and second condition is conventional compressor rack with one VSD compressor. Then energy parameter is recorded by automatic controller. Researcher measure kWh of each compressor, suction temperature, discharge temperature, ambient air temperature, indoor temperature and humidity. Those two condition are switched every day, 1st day is VSD, 2nd day is without VSD and 3rd days is VSD. to 10th days. All parameter are got 5 days per each one condition. All data will be used to find actual consumption and actual cooling capacity of each percentage load. Percentage load can find from turning on and turning off in each hour of compressor. For this stage, Discharge temperature, Suction temperature, kWh and number of turning on and turning off of compressor in each hour, all of parameter can be find to convert to cooling capacity. Then cooling capacity (kWf) can be got from output of computer software (https://www.bitzer.de/websoftware.) The main method is actual measure kWh 10 days to get energy consumption saving by each percentage load, then convert data to cooling capacity ( kWf ) at all experimental time. After that, that saving of kWf by each percentage load can be linked to the whole year evaluation from data recorder.

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2.3.2 Compressor performance comparison to find energy consumption ( kWh ) saving. When we get energy consumption of each percentage load, we can compare both condition of VSD and without VSD. If we see and get energy saving by each percentage load, we can evaluate long term energy saving. That energy saving result by each percentage load will be applied as reference data for long term saving calculation. 2.3.3 Long term evaluation of energy saving from percentage of load profile. Cooling efficiency (kWf) can be found from controller record. When we get kWh saving by each percentage load. Whole year evaluation can be found. 3. Results The results of comparison, Energy consumption of VSD compressor in multi set rack is not saved during 0% 50% load and all actual load are varied between 0 percent to 50 percent. Average energy consumption of VSD compressor set is 37.44 kWh/h, but without VSD is at 32.56 kWh. Energy consumption of VSD compressor is higher than without VSD compressor. That is no saving for VSD compressor comparison with without VSD compressor as is shown in figure 1. 60 50 40

kWh/h

y = 0.4811x + 17.496

30 y = 0.2377x + 28.377

20 10 0

0

10 VSD

20

30 no VSD

40

50

% Load Linear (VSD)

60

70

80

Linear (no VSD)

Figure 1. kWh/h and percentage load of Chiller compressor comparison VSD and without VSD compressor

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kWf/h

The result of cooling capacity ( kWf ) of VSD compressor in multi set rack is not save during 0% -50% load and all actual load are varied between 0 percent to 50 percent same the result of kWh as is shown in figure 2.

 5.00  4.50  4.00  3.50  3.00  2.50  2.00  1.50  1.00  0.50  ‐

y = -0.0083x + 0.7702 y = -0.029x + 1.7183

0

10

20

30

40

VSD Linear ( VSD)

50

60

70

80

no VSD Linear (no VSD) % Load

Figure 2. kWf/h and percentage load of Chiller compressor comparison VSD and without VSD compressor

Total energy consumption of VSD compressor is higher than the one without VSD compressor, since it runs over night. Conventional compressor can be turned off without load at night, while VSD compressor run minimum frequency at night without load. In day time, energy consumption of VSD compressor is lower than the one without VSD compressor. It means that VSD compressor can save energy only at day time and not save at night time as is shown in figure 3. 50 45

without VSD  , Average consumption 32.56kWh

with VSD , Average consumption 37.44kWh

40 35

Kwh

30 25 20 15 10 5 0

192123 1 3 5 7 9 11131517192123 1 3 5 7 9 11131517192123Hour 1 3 5 7 9 11131517192123 1 3 5 7 9 11131517192123 1 3 5 7 9 11131517

Figure 3. Energy consumption ( kWh ) comparison between VSD and without VSD compressor by hour

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4. Discussion Variable speed drive (VSD) describes equipment used to control the speed of machinery. It can operate at different speed for different load demand. If flow of compressor can be adjusted, it may save energy comparing with other techniques of flow control do. This research find the difference from existing belief. For actual operation of chiller machine. It has no cooling load at night time. Without load, the conventional multi set is off. The standard VSD is set to maintain the minimum load or minimum frequency at night time. The total energy consumption of VSD compressor is not saved, although VSD compressor rack is saved at day time. If VSD is set minimum frequency (35 Hz) and turn off for load demand lower than minimum, the simulation is saved of energy consumption of VSD compressor as is show in figure 4.

60

50

40

y = 0.4811x + 17.496 kWh/h

30

20

y = 0.8025x + 2.4916

10

0

0

10

20

30

40

50

60

70

80

% Load VSD

no VSD

Linear (VSD)

Linear (no VSD)

Figure 4. Simulation, kWh/h and percent load of Chiller compressor comparison VSD and without VSD compressor

For this simulation, VSD compressor will be turned off at nigh time and can save energy at day time as is show in figure 5 simulation. Average energy consumption of VSD compressor set is 32.05 kWh/h, but without VSD is at 32.56 kWh.

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VSD_KW‐Hr / Hr

NO VSDKW‐Hr / Hr

Avg.VSD_KW‐Hr/Hr

13

Avg.KW‐Hr/Hr

45 40 35 30 25

kWh

20 15 10 5 0

19 22 1 4 7 10 13 16 19 22 1 4 7 10 13 16 19 22 1 4 7 10 13 16 19 22 1 4 7 10 13 16 19 22 1 4 7 10 13 16

Hour

Figure 5. Simulation, Energy consumption (kWh) comparison between VSD and without VSD compressor by hour

5. Conclusion The result of this experimental to prove VSD compressor in refrigeration system, the measurement in actual activity in retail and whole sale building 10,000 sq.m. building area and 7,000 sq.m. sale area found that VSD compressor not save for the whole day. But it can save only day time. The night time cannot save. The recommendation from this research is to improve this system to get saving from VSD compressor. VSD system need to set additional function to turn off at night or turn off at no load demand. References [1] Department of alternative energy development and efficiency. 2015 [2] Electricity generating authority of Thailand, Published document of energy saving technology knowledge, Variable speed drive VSD,2015