scholarly journals WASTE HEAT GENERATION AND POTENTIAL RECOVERY SYSTEMS USED IN SRI LANKAN HOTELS

2021 ◽  
Author(s):  
N. Lakshan ◽  
◽  
T. Ramachandra ◽  
U.G.D. Madushika ◽  
◽  
...  

The waste heat recovery concept can be used as a solution to optimise energy consumption while reducing the waste heat in energy generation systems. However, its application in Sri Lankan hotels is still in the infancy stage even though the hotel sector accounts for high energy consumption. Therefore, this research aimed to assess the amount of waste heat generated from the different sources in hotel buildings and thereby identify the most appropriate waste heat recovery systems to the hotel buildings in Sri Lanka through a comparative case study analysis of three similar natured hotel buildings. The required data to perform waste heat calculation were extracted through document reviews and site visits. This study identified the three main waste heat generating sources in hotel buildings: HVAC condenser out, boiler exhaust, and kitchen exhaust. The analysis shows that the condenser out of the HVAC system is the highest waste heat generating source which accounts for an average of 41,823GJ per year while boiler exhaust and kitchen exhaust generate the waste heat of an average of 11,000GJ and 8GJ per year. It is further found that the quality of waste heat generated from the boiler exhaust is higher than the condenser out of the HVAC system and kitchen exhaust. Hence, this study concludes that the boiler has the highest potential of using the waste heat recovery system than the condenser out of the HVAC.

2014 ◽  
Vol 577 ◽  
pp. 564-567 ◽  
Author(s):  
Fang Tian Sun ◽  
Cui Jie Li ◽  
Rui Xiang Wang ◽  
De Ying Li

Two waste heat recovery systems of barbershops were presented to increase its heat utilization efficiency. One was the waste heat recovery system with water-to-water heat exchanger (WHR-HE). The other is the waste heat recovery system with both water-to-water heat exchanger and heat pump (WHR-HE-HP). The two waste heat recovery systems were analyzed by both economics and thermodynamics principles. Compared to conventional heat utilization systems of barbershops, the WHR-HE decreases annual energy consumption by 54.2%, and the WHR-HE-HP decreases annual energy consumption by 87.5%. The gain investment recovery periods of WHR-HE and WHR-HE-HP are below half one year. Compared to the WHR-HE, the WHR-HE-HP is with larger energy-saving potential, lower running cost, larger first cost and larger gain investment recovery period. The critical value of energy-saving financial subsidy is 0.778 ¥/W for the WHR-HE-HP. The WHR-HE-HP is very suited to the large and medium-sized barbershops, especially in the cold climate zone.


2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Gunabal S

Waste heat recovery systems are used to recover the waste heat in all possible ways. It saves the energy and reduces the man power and materials. Heat pipes have the ability to improve the effectiveness of waste heat recovery system. The present investigation focuses to recover the heat from Heating, Ventilation, and Air Condition system (HVAC) with two different working fluids refrigerant(R410a) and nano refrigerant (R410a+Al2O3). Design of experiment was employed, to fix the number of trials. Fresh air temperature, flow rate of air, filling ratio and volume of nano particles are considered as factors. The effectiveness is considered as response. The results were analyzed using Response Surface Methodology


2021 ◽  
Vol 234 ◽  
pp. 113947
Author(s):  
Alexandre Persuhn Morawski ◽  
Leonardo Rodrigues de Araújo ◽  
Manuel Salazar Schiaffino ◽  
Renan Cristofori de Oliveira ◽  
André Chun ◽  
...  

2012 ◽  
Vol 204-208 ◽  
pp. 4229-4233 ◽  
Author(s):  
Fang Tian Sun ◽  
Na Wang ◽  
Yun Ze Fan ◽  
De Ying Li

Drain water at 35°C was directly discharged into sewer in most of barbershop with Electric water heater. Heat utilization efficiency is lower, and energy grade match between input and output is not appropriate in most of barbershops. Two waste heat recovery systems were presented according to the heat utilization characteristics of barbershops and principle of cascade utilization of energy. One was the waste heat recovery system by water-to-water heat exchanger (WHR-HE), and the other is the waste heat recovery system by water-to-water heat exchanger and high-temperature heat pump (WHR-CHEHP). The two heat recovery systems were analyzed by the first and second Laws of thermodynamic. The analyzed results show that the energy consumption can be reduced about 75% for HR-HE, and about 98% for WHR-CHEHP. Both WHR-HE and WHR-CHEHP are with better energy-saving effect and economic benefits.


Author(s):  
Salman Abdu ◽  
Song Zhou ◽  
Malachy Orji

Highly increased fuel prices and the need for greenhouse emissions reduction from diesel engines used in marine engines in compliance with International Maritime Organization (IMO) on the strict regulations and guidelines for the Energy Efficiency Design Index (EEDI) make diesel engine exhaust gas heat recovery technologies attractive. The recovery and utilization of waste heat not only conserves fuel, but also reduces the amount of waste heat and greenhouse gases dumped to the environment .The present paper deals with the use of exergy as an efficient tool to measure the quantity and quality of energy extracted from waste heat exhaust gases in a marine diesel engine. This analysis is utilized to identify the sources of losses in useful energy within the components of the system for three different configurations of waste heat recovery system considered. The second law efficiency and the exergy destroyed of the components are investigated to show the performance of the system in order to select the most efficient waste heat recovery system. The effects of ambient temperature are also investigated in order to see how the system performance changes with the change of ambient temperature. The results of the analysis show that in all of the three different cases the boiler is the main source of exergy destruction and the site of dominant irreversibility in the whole system it accounts alone for (31-52%) of losses in the system followed by steam turbine and gas turbine each accounting for 13.5-27.5% and 5.5-15% respectively. Case 1 waste heat recovery system has the highest exergetic efficiency and case 3 has the least exergetic efficiency.


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