scholarly journals Thermodynamic Optimization of Cascade Heat Pump

2020 ◽  
Author(s):  
Ivana Kovačević ◽  
◽  
Ne Rudonja ◽  
Milan Gojak
Keyword(s):  
Heat Pump ◽  
Thermodynamic Analysis ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Heat Pumps ◽  
Intermediate Temperature ◽  
Working Fluid ◽  
Modern World ◽  
Thermodynamic Optimization ◽  
The Impact

In today’s modern world, development of industry and technology has led to the increase in energy demand. Hence, more fossil fuels are burnt in order to cover this demand. Due to the multiple disadvantages, as well as the negative impact that burning of fossil fuels has on the environment, heat pumps are gaining more importance when providing energy for heating. This paper is aimed at conducting thermodynamic optimization of cascade heat pump in terms of different working fluid combinations and calculating maximum COP. In order to perform thermodynamic analysis, a software program that uses database of working fluids, was developed. The intermediate temperature within cascade heat exchanger represents a crucial parameter when analyzing and designing cascade heat pumps. Thus, when performing thermodynamic analysis, the intermediate temperature was varied in the range from 0°С to 25°С and the optimal temperature that provides maximum COP was defined. The analysis was performed on an air–to–water heat pump, that could be used for heating different types of buildings in places in Serbia where the outdoor design temperature is –20°С. The cascade heat pump would be used alongside radiator heating system operating at temperatures 70°С/50°С. Due to the high temperature difference between heat source and heat sink, cascade heat pumps have advantages over single stage or multi stage heat pumps. The optimization was performed on an air–to–water cascade heat pump where the evaporation and condensation temperatures were –25°С and 75°С, respectively. Following the conducted optimization, the analysis of the impact that isentropic efficiency of compressor has on COP was examined.

scholarly journals Sensitivity analysis using simulations for a ground source heat pump – implementation on a solar passive house

2019 ◽  
Vol 111 ◽  
pp. 01070
Author(s):  
Gheorghe Ilisei ◽  
Tiberiu Catalina ◽  
Robert Gavriliuc
Keyword(s):  
Sensitivity Analysis ◽  
Heat Pump ◽  
Fossil Fuels ◽  
Electricity Consumption ◽  
Heat Pumps ◽  
Ground Source Heat Pump ◽  
Passive House ◽  
Modeling Tools ◽  
Ground Source Heat Pumps ◽  
Ground Source

Having in sight the need for a strong reduction in CO2 emissions and the fluctuation of the price of fossil fuels, the ground source resources alongside with the ground source heat pumps are becoming more and more widespread for meeting the heating/cooling demand of several types of buildings. This article targets to develop the thermal modelling of borehole heat storage systems. Trying to emphasize some certain advantages of a GSHP (ground source heat pump) with vertical boreholes, a case study analysing a residential solar passive house is presented. The numerical results are produced using different modelling software like DesignBuilder, EED (Earth Energy Designer) and a sizing method for the length of the boreholes (ASHRAE method). The idea of sizing the length of boreholes (main design parameter and good index in estimating the system’s cost) using two different methods shows the reliability of this modelling tool. The study shows that borehole’s length of a GSHP system can trigger a difference in electricity consumption up to 22%. Moreover, this sensitivity analysis aims to prove that the design of the whole system can be done beforehand just using modeling tools, without performing tests in-situ.

scholarly journals Economic Analysis and Environmental Impact Assessment of Heat Pump-Assisted Distillation in a Gas Fractionation Unit

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 852 ◽  
Author(s):  
Jisook Lee ◽  
Yongho Son ◽  
Kwang Lee ◽  
Wangyun Won
Keyword(s):  
Environmental Impact ◽  
Economic Analysis ◽  
Impact Assessment ◽  
Heat Pump ◽  
Environmental Impact Assessment ◽  
Fossil Fuels ◽  
New Technologies ◽  
Heat Pumps ◽  
Environmental Drivers ◽  
Feed Composition

The depletion of fossil fuels and environmental pollution (e.g., greenhouse gas emissions) through the combustion of fossil fuels have stimulated studies on new technologies able to curtail the energy consumption of existing fractionation units. In this regard, heat pumps have garnered substantial attention due to their potential to improve the process energy efficiency. This study aims to provide extensive economic analysis and environmental impact assessment of the application of heat pumps under different conditions and scenarios. For this purpose, we first selected three important conditions: feed composition, plant capacity, and fuel price. Then, we performed a range of analyses to identify the major costs and environmental drivers. The economics and environmental impact of heat pump-assisted distillation was investigated and compared with those of conventional distillation.

Energy Saving and Emission Reduction in Power Generation Sector for China’s Heat Pump Heating

2012 ◽  
Vol 608-609 ◽  
pp. 961-964
Author(s):  
Xia Chen ◽  
Li Wang ◽  
Li Ge Tong ◽  
Shu Feng Sun ◽  
Xian Fang Yue ◽  
...  
Keyword(s):  
Power Generation ◽  
Energy Saving ◽  
Heat Pump ◽  
Emission Reduction ◽  
Co2 Emission ◽  
Positive Impact ◽  
Current Trend ◽  
Northern China ◽  
Heat Pumps ◽  
The Impact

China is ranked as the world’s largest emitter of carbon dioxide (CO2). The CO2 emission from urban central heating (UCH) is responsible for 4.4% of China’s total CO2 emission. It is proposed that heat pump heating (HPH) could serve as a replacement for UCH to help realize energy-saving and emission-reduction goals to a greater extent. In northern China, 30% of urban building area is covered by urban decentralized heating (UDH). Replacing UDH with HPH is the current trend in China. In this paper we analyze the impact of replacing coal with heat pumps on the power generation sector in China. The results show that HPH has a positive impact on the power generation sector. By considering simultaneous replacement of UCH and UDH with HPH, the efficiency of power generation at the valley electricity time is increased by 0.512%; the ratio of peak–valley difference is decreased by 25.3%; the obtained reduction of CO2 emission cumulatively contributes to approximately 10.96% of this target.

Surge Onset in Turbo Heat Pumps

2014 ◽  
Vol 136 (8) ◽  
Author(s):  
Jieun Song ◽  
Jung Chan Park ◽  
Kil Young Kim ◽  
Jinhee Jeong ◽  
Seung Jin Song
Keyword(s):  
Heat Pump ◽  
Heat Exchangers ◽  
Heat Pumps ◽  
Working Fluid ◽  
Pump System ◽  
Heat Pump System ◽  
Linearized Stability ◽  
Stability Model ◽  
Expansion Valve ◽  
Mass Spring

A typical turbo heat pump system consists of a centrifugal compressor, expansion valve, and two heat exchangers—a condenser and evaporator. Compared to a gas turbine, a turbo heat pump introduces additional complexities because it is a two-phase closed-loop system with heat exchange using a real gas/liquid (refrigerant) as the working fluid. For the first time, surge onset in such systems has been physically, analytically, and experimentally investigated. This study analytically investigates the physical mechanisms of surge onset in turbo heat pumps. From an existing nonlinear turbo heat pump surge model, the turbo heat pump is viewed as a mass-spring-damper system with two inertias, two dampers, and four springs which is then further simplified to a single degree-of-freedom system. Surge onset occurs when the system damping becomes zero and depends not only the compressor but also on the ducts, heat exchangers, and expansion valve. Alternatively, a new stability model has been developed by applying a linearized small perturbation method to the nonlinear turbo heat pump surge model. When the new linear stability model is applied to a conventional open loop compression system (e.g., a turbocharger), predictions identical to those of Greitzer's model are obtained. In addition, surge onset has been experimentally measured in two turbo heat pumps. A comparison of the predictions and measurements shows that the mass-spring-damper model and the linearized stability model can accurately predict the turbo heat pump surge onset and the mass-spring-damper model can explain the turbo heat pump surge onset mechanisms and parametric trends in turbo heat pumps.

scholarly journals Assessment on the Efficiency of an Active Solar Thermal Facade: Study of the Effect of Dynamic Parameters and Experimental Analysis When Coupled/Uncoupled to a Heat Pump

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 597
Author(s):  
Peru Elguezabal ◽  
Alex Lopez ◽  
Jesus Maria Blanco ◽  
Jose Antonio Chica
Keyword(s):  
Energy Efficiency ◽  
Heat Pump ◽  
Poor Performance ◽  
Heat Pumps ◽  
Solar Thermal ◽  
Solar Irradiation ◽  
Active System ◽  
Building Sector ◽  
Improve Energy Efficiency ◽  
The Impact

The building sector presents poor performance in terms of energy efficiency and is looking for effective alternatives aimed at reducing the use of fossil fuels. The facade is a key element able to harness renewable energy as an Active Solar Thermal Facade (ASTF). The main purpose of this study is the assessment of a novel design concept based on a steel sandwich panel technology. The performance of the active system will be first addressed by a parametric study in order to analyze its behavior and secondly, by describing a real case based on an experimental test by connecting the active panels to a heat pump. The study shows the impact of solar irradiation and mass flow on the thermal jump achieved, while ambient and fluid inlet temperatures are the most influencing parameters in the efficiency of the facade. When coupled to the heat pump, results from a measurement campaign demonstrate a remarkable improvement in the performance of the ASTF. The results presented provide significant proof about the benefits of a synergetic combination of both technologies—solar facades and heat pumps—as efficient alternatives for the building sector, aiming to improve energy efficiency as well as reduce their dependence on non-renewable sources.

scholarly journals Influence of desorption temperature on the thermodynamic performance of adsorption heat pump

2018 ◽  
Vol 70 ◽  
pp. 01022
Author(s):  
Katarzyna Zwarycz-Makles
Keyword(s):  
Heat Pump ◽  
Heat Pumps ◽  
Adsorption Heat ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Thermodynamic Efficiency ◽  
Efficiency Coefficient ◽  
Desorption Temperature ◽  
Adsorption Heat Pump ◽  
Thermodynamic Performance

In the paper an analysis of the desorption temperature effect on the thermodynamic efficiency of the adsorption heat pumps is presented. The thermodynamic performance of heat pump is determined by Coefficient of Performance (COP) as well as exergetic efficiency coefficient (ηex) at the adsorption equilibrium conditions and compared to the performance at heat of evaporation of the working fluid conditions. Possible estimation of reduced efficiency of adsorption silica gel/water heat pump, as distinct from the equilibrium efficiency in realistic technical system is presented.

Thermodynamic Analysis of Ejector as an Expansion Device on Split-Type Air Conditioner Using R410A as Working Fluid

2014 ◽  
Vol 493 ◽  
pp. 227-232 ◽  
Author(s):  
Kasni Sumeru ◽  
Henry Nasution ◽  
Farid Nasir Ani
Keyword(s):  
Numerical Modeling ◽  
Thermodynamic Analysis ◽  
Negative Impact ◽  
Capillary Tube ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Air Conditioner

Typically the split-type air conditioner uses a capillary tube as expansion device. To enhance the performance of the system, an ejector can be applied as expansion device to replace capillary tube. Based on the numerical modeling, the coefficient of performance (COP) of standard cycle using R410A as working fluid was slightly lower than that of R22. The use of an ejector as an expansion device on a split-type air conditioner using R410 increased the COP by 10.8%. Also, R410A has a lower total GWP impact compared with R22, which reduce negative impact on the environment.

Properties of Self-Compacting Geopolymer Concrete

2014 ◽  
Vol 803 ◽  
pp. 99-109 ◽  
Author(s):  
Muhd Fadhil Nuruddin ◽  
Fareed Ahmed Memon
Keyword(s):  
Construction Industry ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Raw Materials ◽  
Construction Material ◽  
Construction Materials ◽  
Cement Production ◽  
Cement Manufacture ◽  
The Moment ◽  
The Impact

Concrete has been used in the construction industry since long times. It is probably the most widely used construction material in the world, largely due to the abundance of the raw materials for cement manufacture, low relative cost and the versatility and adaptability of concrete in forming various structural shapes. Massive production of concrete and the associated substantial manufacture of cement have however been observed to have a very negative impact. One of the biggest issues of growing concern at the moment faced by concrete industries is the impact of cement production on the environment. The production of cement not only depletes significant amount of natural resources, but also liberates a considerable amount of carbon dioxide (CO2) and other greenhouse gases into the atmosphere as a result of decarbonation of limestone and the combustion of fossil fuels. In addition, cement is among the most energy intensive construction materials, after aluminium and steel [1].

scholarly journals Does Geopolitics Have an Impact on Energy Trade? Empirical Research on Emerging Countries

2021 ◽  
Vol 13 (9) ◽  
pp. 5199
Author(s):  
Fen Li ◽  
Cunyi Yang ◽  
Zhenghui Li ◽  
Pierre Failler
Keyword(s):  
Fossil Fuels ◽  
Negative Impact ◽  
Fixed Effect Model ◽  
Mediating Effect ◽  
Crude Oil Prices ◽  
Energy Trade ◽  
Natural Gas Prices ◽  
Significant Negative Impact ◽  
The Impact ◽  
Geopolitical Risks

The energy trade is an important pillar of each country’s development, making up for the imbalance in the production and consumption of fossil fuels. Geopolitical risks affect the energy trade of various countries to a certain extent, but the causes of geopolitical risks are complex, and energy trade also involves many aspects, so the impact of geopolitics on energy trade is also complex. Based on the monthly data from 2000 to 2020 of 17 emerging economies, this paper employs the fixed-effect model and the regression-discontinuity (RD) model to verify the negative impact of geopolitics on energy trade first and then analyze the mechanism and heterogeneity of the impact. The following conclusions are drawn: First, geopolitics has a significant negative impact on the import and export of the energy trade, and the inhibition on the export is greater than that on the import. Second, the impact mechanism of geopolitics on the energy trade is reflected in the lagging effect and mediating effect on the imports and exports; that is, the negative impact of geopolitics on energy trade continued to be significant 10 months later. Coal and crude oil prices, as mediating variables, decreased to reduce the imports and exports, whereas natural gas prices showed an increase. Third, the impact of geopolitics on energy trade is heterogeneous in terms of national attribute characteristics and geo-event types.

scholarly journals Impact study of the fuel type used on the energy efficiency costs values and harmful emissions generation for small, medium and large container vessels

2021 ◽  
Vol 327 ◽  
pp. 02006
Author(s):  
Viktor Nikiforov ◽  
Irina Kostova
Keyword(s):  
Greenhouse Gases ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Fuel Type ◽  
Harmful Emissions ◽  
Negative Effect ◽  
Large Container ◽  
State Of The Environment ◽  
The Impact

Annually a large amount of goods has been transported over the world and the most of the transportation is carried by seaborne. Although the seaborne trade is considered to be the most efficient – economically and environmentally friendly way of transportation an enormous amount of fossil fuels is used to fulfil the operation of the merchant fleet. Although we are living in times where efforts are directed to improvement of the state of the environment and reduction of the negative impact of the Greenhouse Gases, the fossil fuels still remain the main energy source used to run the internal combustion engines widely used in the ships nowadays. A well-known fact is that the fuel burning leads to significant harmful emissions generation causing a serious negative effect on the surrounding us environment. The introduced by IMO and MEPC requirements regarding the Greenhouse Gases (GHG) imposes for development and application of new criteria when selecting the ship’s propulsion plant. In the current article will be observed three ship groups consisting of real container vessels. The purpose is to analyse the impact caused by the fuel type used in the ship’s engines on the GHG generation and the economic indicators related with fuel costs

Sign in / Sign up

Export Citation Format

Share Document