ASHRAE Journal - August 2019 - 41

TECHNICAL FEATURE

Environmental Analysis

FIGURE 19 CO2 emissions and CO2 emission reduction per year function of recovery chiller (RC) capacity and

CO2 Emissions Reduction (%)

CO2 Emissions Per Year (Tonnes)

For the environmental analysis,
leaving hot water temperature water temperature leaving the RC.
the following CO2 emission rates are
5,600
16
considered:16
14
5,500
* LPG CO2 emission rate:
12
5,400
0.49 lb CO2/kWh (0.22 kg CO2/kWh);
10
and
5,300
* Electricity CO2 emission
8
5,200
rate in Qatar: 1.3 lb CO2/kWh
6
5,100
(0.596 kg CO2/kWh).
4
5,000
Figure 19 shows, respectively,
2
the CO2 emissions and CO2 emis4,900
sion reduction function of recov0
4,800
ery chiller capacity and leaving
0
200
400
600
800
1,000 1,200 1,400 1,600 1,800 2,000
Recovery Chiller Heat Capacity (kW)
hot water temperature. It shows
clearly the decrease in CO2 emisHot Water RC 40
Hot Water RC 45
Hot Water RC 50
sions when substituting part of
Hot Water RC 55
Hot Water RC 60
the LPG boiler with heat recovery
chillers.
and Opportunities in U.S. Industry", prepared for the U.S.
By adding the recovery chiller to the utility plant, the
Department of Energy, Industrial Technologies Program.
CO2 emissions can be reduced by 11% and 13%, respec2. Thekdi A. 2014. "Industrial Waste Heat Recovery: Potential
tively, for 104°F (40°C) and 140°F (60°C) recovery chiller Applications, Available Technologies and Crosscutting R&D
Opportunities." Oak Ridge National Laboratory (ORNL).
leaving hot water temperatures.
3. ASHRAE. 2004. "Applied Heat Pump and Heat Recovery
Even though electricity in Qatar has higher speciﬁc
Systems," ASHRAE HVAC Systems and Equipment Handbook, p.
CO2 emissions than LPG-speciﬁc CO2 emissions in
8.20, Atlanta, GA.
4. Carbon Trust. 2011. "How to implement heat recovery
kg CO2/kWh, substituting part of the LPG boiler will
in refrigeration - Recovering waste heat produced by the
decrease greenhouse gas (GHG) emissions due to the
refrigeration process can save energy and cut costs."
dual performance of the recovery chiller and the higher
5. NASA. 2017. National Aeronautics and Space Administration.
energy conversion factor for heat pumps.
"Global Climate Change- Vital Signs of the Planet".

Discussions and Conclusions
Energy recovery systems are widely recognized as efﬁcient systems with a great potential to reach important
energy and economic savings. In addition, as an environmentally friendly solution they are pointed out as
a technology to be promoted. In this case study, a CCH
system lowering LPG boilers' contribution is proposed.
A modeling and optimization method was developed
for the cooling/heating system to achieve optimal operation. The model takes into account the energy balances,
power, heating and cooling demands.
The modeling and optimization method was performed using in-house software and demonstrated that
lifetime cost savings of almost 20% can be reached.

References
1. BCS, Incorporated. 2008. "Waste Heat Recovery: Technology

6. Schwedler, M. 2007, "Water-side heat recovery." Trane
Engineers Newsletter volume 36-1.
7. Carrier. 2008. "Heat Recovery from Chilled Water Systems Applications for Heat Reclaim Chillers."
8. Meteonorm 2017. Version 7.2 data.
9. Weatherspark 2018. https://weatherspark.com/y/105083/
Average-Weather-in-Doha-Qatar-Year-Round#SectionsTemperature.
10. Johnson Controls, Inc. 2013. "Heat Pump Chillers" York
Industrial Systems.
11. Trane. 2016. "Sintesis RTAF air-cooled chillers" RLCPRC046D-GB.
12. Brent, S. 2014. "Utilizing Heat Recovery Effectively" - Carrier
Corporation.
13. Daikin. 2009. "EWAD Air-cooled Heat Recovery Chillers"
Daikin Europe N.V. ECPEN09-417.
14. WOQOD 2018, Qatar Fuel. http://www.woqod.com.
15. KAHRAMAA 2018, Qatar General Electricity & Water
Corporation, https://www.km.com.qa.
16. Brander, M. 2011. "Electricity-speciﬁc emission factors
for grid electricity." https://ecometrica.com/assets/Electricityspeciﬁc-emission-factors-for-grid-electricity.pdf.
A U G U S T 2 0 19

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https://weatherspark.com/y/105083/Average-Weather-in-Doha-Qatar-Year-Round#Sections-Temperature https://weatherspark.com/y/105083/Average-Weather-in-Doha-Qatar-Year-Round#Sections-Temperature http://www.woqod.com https://www.km.com.qa https://ecometrica.com/assets/Electricity-specific-emission-factors-for-grid-electricity.pdf https://ecometrica.com/assets/Electricity-specific-emission-factors-for-grid-electricity.pdf https://www.ashrae.org/

ASHRAE Journal - August 2019

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