scholarly journals Recovery and Utilization of Low-Grade Waste Heat in the Oil-Refining Industry Using Heat Engines and Heat Pumps: An International Technoeconomic Comparison

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2560 ◽  
Author(s):  
Nikunj Gangar ◽  
Sandro Macchietto ◽  
Christos N. Markides
Keyword(s):  
Heat Source ◽  
Thermal Energy ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Oil Refining ◽  
Low Grade ◽  
Energy Prices ◽  
Steam Generation ◽  
Electricity Prices ◽  
Oil Refineries

We assess the technoeconomic feasibility of onsite electricity and steam generation from recovered low-grade thermal energy in oil refineries using organic Rankine cycle (ORC) engines and mechanical vapour compression (MVC) heat pumps in various countries. The efficiencies of 34 ORC and 20 MVC current commercial systems are regressed against modified theoretical models. The resulting theoretical relations predict the thermal efficiency of commercial ORC engines within 4–5% and the coefficient of performance (COP) of commercial MVC heat pumps within 10–15%, on average. Using these models, the economic viability of ORC engines and MVC heat pumps is then assessed for 19 refinery streams as a function of heat source and sink temperatures, and the available stream thermal energy, for gas and electricity prices in selected countries. Results show that: (i) conversion to electrical power with ORC engines is, in general, economically feasible for heat-source temperatures >70 °C, however with high sensitivity to energy prices; and (ii) steam generation in MVC heat pumps, even more sensitive to energy prices, is in some cases not economical under any conditions—it is only viable with high gas/low electricity prices, for large heat sources (>2 MW) and higher temperatures (>140 °C). In countries and conditions with positive economics, payback periods down to two years are found for both technologies.

scholarly journals Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

2020 ◽  
Vol 12 (19) ◽  
pp. 8178
Author(s):  
Fahid Riaz ◽  
Kah Hoe Tan ◽  
Muhammad Farooq ◽  
Muhammad Imran ◽  
Poh Seng Lee
Keyword(s):  
Low Temperature ◽  
Thermal Energy ◽  
Waste Heat ◽  
Solar Thermal ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Low Grade ◽  
Solar Thermal Energy ◽  
Temperature Heat ◽  
Vapour Compression

Low-grade heat is abundantly available as solar thermal energy and as industrial waste heat. Non concentrating solar collectors can provide heat with temperatures 75–100 °C. In this paper, a new system is proposed and analyzed which enhances the electrical coefficient of performance (COP) of vapour compression cycle (VCC) by incorporating low-temperature heat-driven ejectors. This novel system, ejector enhanced vapour compression refrigeration cycle (EEVCRC), significantly increases the electrical COP of the system while utilizing abundantly available low-temperature solar or waste heat (below 100 °C). This system uses two ejectors in an innovative way such that the higher-pressure ejector is used at the downstream of the electrically driven compressor to help reduce the delivery pressure for the electrical compressor. The lower pressure ejector is used to reduce the quality of wet vapour at the entrance of the evaporator. This system has been modelled in Engineering Equation Solver (EES) and its performance is theoretically compared with conventional VCC, enhanced ejector refrigeration system (EERS), and ejection-compression system (ECS). The proposed EEVCRC gives better electrical COP as compared to all the three systems. The parametric study has been conducted and it is found that the COP of the proposed system increases exponentially at lower condensation temperature and higher evaporator temperature. At 50 °C condenser temperature, the electrical COP of EEVCRC is 50% higher than conventional VCC while at 35 °C, the electrical COP of EEVCRC is 90% higher than conventional VCC. For the higher temperature heat source, and hence the higher generator temperatures, the electrical COP of EEVCRC increases linearly while there is no increase in the electrical COP for ECS. The better global COP indicates that a small solar collector will be needed if this system is driven by solar thermal energy. It is found that by using the second ejector at the upstream of the electrical compressor, the electrical COP is increased by 49.2% as compared to a single ejector system.

The Potential for Integrating Solar Thermal Energy in Both Centralized and Decentralized Systems in Egypt

2018 ◽  
Author(s):  
Ramy Imam ◽  
Mohamed Yassin
Keyword(s):  
Power Generation ◽  
Renewable Energy ◽  
Developing Country ◽  
Thermal Energy ◽  
Solar Thermal ◽  
Energy Prices ◽  
Solar Thermal Energy ◽  
Electricity Prices ◽  
Renewable Energy Technologies ◽  
Energy Technologies

There is an increasing need for the integration of renewable energy into the energy sector in Egypt. As the electricity subsidies are residing for consumers in Egypt, electricity prices are increasing. This increase in energy prices can be mitigated by the integration of renewable energy technologies. One of the most promising renewable energy technologies that will help stabilize the energy situation in Egypt, is Solar Thermal Energy. Solar Thermal Energy has a great potential in Egypt due to the availability and intensity of direct irradiance in Egypt. Therefore, Egypt has an amazing opportunity as a developing country to start perusing solar thermal technologies; these technologies include decentralized and centralized technologies. Decentralized technologies are targeted more for regular consumers and centralized technologies are targeted more for power generation and industries.

Thermohydraulic Analysis of Ground as a Heat Source for Heat Pumps Using Vertical Pipes

1996 ◽  
Vol 118 (4) ◽  
pp. 300-305 ◽  
Author(s):  
M. T. Kangas
Keyword(s):  
Computer Simulation ◽  
Heat Source ◽  
Heat Pump ◽  
Thermal Energy ◽  
System Performance ◽  
Thermal Effects ◽  
Heat Pumps ◽  
The Other ◽  
Heat Extraction ◽  
Energy Potential

In this study, the use of the ground as the heat source for a heat pump was studied by computer simulation. The heat extraction system consisted of vertical pipes drilled into the ground where groundwater was present. Along with available thermal energy, potential environmental effects, such as freezing and thermal pollution, were examined. It was found that the presence of groundwater enhances system performance by decreasing the possibility of freezing but, on the other hand, increases the range of thermal effects in the ground. The temperature of the ground as well as extraction arrangements also have a significant effect on system performance.

Performance Study of Waste Heat Driven Pressurized Adsorption Chiller

2013 ◽  
Vol 315 ◽  
pp. 380-384
Author(s):  
Khairul Habib
Keyword(s):  
Heat Source ◽  
Waste Heat ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Performance Study ◽  
Adsorption Chiller ◽  
And Performance ◽  
Low Grade Heat ◽  
Adsorption Desorption

This article presents a transient modeling and performance of a waste heat driven pressurized adsorption chiller. This innovative adsorption chiller employs pitch based activated carbon of type Maxsorb III as adsorbent and R507A as refrigerant as adsorbent-refrigerant pair. This chiller utilizes low-grade heat source to power the cycle. A parametric study has been presented where the effects of adsorption/desorption cycle time, switching time and regeneration temperature on the performance are reported in terms of cooling capacity and coefficient of performance (COP). Results indicate that the adsorption chiller is feasible even when low-temperature heat source is available.

scholarly journals Portable Heat Pump Testing Device

2015 ◽  
Vol 20 (3) ◽  
pp. 657-662
Author(s):  
R. Kłosowiak ◽  
J. Bartoszewicz ◽  
R. Urbaniak
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Reverse Flow ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Testing Device ◽  
Flow Cycle ◽  
Working Principle ◽  
Pump Testing ◽  
Control And Measurement System

Abstract The aim of this paper is to present the design and working principle of a portable testing device for heat pumps in the energy recirculation system. The presented test stand can be used for any refrigerating/reverse flow cycle device to calculate the device energy balance. The equipment is made of two portable containers of the capacity of 250 liters to simulate the air heat source and ground heat source with a system of temperature stabilization, compressor heat pump of the coefficient of performance (COP) of = 4.3, a failsafe system and a control and measurement system.

scholarly journals Efficiency of use of waste heat energy on the example of Chelyabinsk

2019 ◽  
Vol 140 ◽  
pp. 11003
Author(s):  
Grigoriy Tseyzer ◽  
Olga Ptashkina-Girina ◽  
Olga Guseva
Keyword(s):  
Thermal Energy ◽  
Waste Heat ◽  
Heat Pumps ◽  
Heat Output ◽  
Low Grade ◽  
Heat Sources ◽  
Sources Of Information ◽  
Equivalent Fuel ◽  
Low Grade Heat

We consider the possibility of improving the existing heat-suppling system in Chelyabinsk through the introduction of heat pump technology for the disposal of waste low-grade heat. Sources of information concerning the ways of utilization of waste thermal energy, the principles of work of heat pumps, classification of city sources of waste heat are analyzed. The technique directed to assess the effectiveness of applying heat pumps for each category of city sources of waste thermal energy is designed. The calculated assessment showed that the utilization of waste heat in the conditions of Chelyabinsk will reduce the annual energy of fuel consumption by 2.2 million tons of conventional fuel (24.9%). At the same time, thermal pollution will decrease by 1.5 million tons of equivalent fuel. This effect is possible with the use of heat pumps with a total heat output of 1,145 MW.

scholarly journals Low to very high temperature thermal energy recycling – 3 case studies

2021 ◽  
Vol 313 ◽  
pp. 09001
Author(s):  
Arne Høeg ◽  
Tor-Martin Tveit
Keyword(s):  
High Temperature ◽  
Heat Source ◽  
Case Studies ◽  
Heat Pump ◽  
Thermal Energy ◽  
West Coast ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
The West ◽  
Very High

In this paper we present three case studies of the installation of a stirling-cycle high temperature heat pump applied to recycling thermal energy including steam generation. Many industries have heat demand at temperatures above 100°C and often the preferred energy carrier is steam. The optimal integration of a heat pump can be determined by investigating the thermal need of the process with pinch technology. For many industries, the pinch temperature is too high for conventional heat pumps. We present a heat pump solution that can recycle thermal energy and deliver this to a heat source up to 200°C, as hot water or steam. The heat pump can be integrated in a thermodynamic efficient way placing the sink and source in-between the pinch temperature. The working medium is a gas throughout the process cycle, with no evaporation or condensation. Thus, the process can auto-adjust to temperature variations and achieve very high efficiencies compared to the Carnot heat pump cycle. The coefficient of performance (COP) of the heat pump vary with the sink/source temperatures as the temperature fraction varies. Another important feature is that the medium has both a global warming potential (GWP) and ozone depletion potential (ODP) of zero. The thermodynamics of the heat pump is explained in more detail in the introduction section. The first installation is at a dairy plant on the west coast of Norway. In this installation, the heat pump provides cooling at 0-5°C and converts this heat into hot water at 120°C. The second installation is also at a dairy in Norway. Here the heat pump cools the ammonia from the cooling compressors at about 25-30°C and converts the heat to hot water at 110C°. The third installation is at a beverage plant on the west coast of Norway. Here the heat pump is providing cooling to compressors and other equipment. The final temperature of the heat source varies from 20-70°C. The heat is converted into steam at 168°C. In the case study sections, the installations are discussed in more details, together with the performance and a discussion of the experiences with the technology.

Sign in / Sign up

Export Citation Format

Share Document