scholarly journals To Pump or Not to Pump? Heat Pump Strategies and Payoffs

1982 ◽  
Author(s):  
Joel S. Gilbert
Keyword(s):  
Heat Flow ◽  
Heat Pump ◽  
Waste Heat ◽  
Heat Pumps ◽  
Economic Viability ◽  
Heat Sources ◽  
Hot Air ◽  
Near Term ◽  
Source And Sink

After several evaluations of waste heat sources and designing heat pumps to recover energy, it has become very apparent that there is a great deal of confusion about just what makes a heat pump economic. The purpose of this article is to look into the design and economics of heat pump systems to determine what makes certain heat pump applications winners and others losers. Steam recompression and generation of steam from moist hot air are investigated specifically. Actual commercially available equipment is considered to determine the near-term and future economic viability of each approach as a function of the source and sink temperatures and magnitude of heat flow. Paper published with permission.

scholarly journals Critical Analysis of Process Integration Options for Joule-Cycle and Conventional Heat Pumps

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 635 ◽  
Author(s):  
Limei Gai ◽  
Petar Sabev Varbanov ◽  
Timothy Gordon Walmsley ◽  
Jiří Jaromír Klemeš
Keyword(s):  
Heat Pump ◽  
Process Integration ◽  
Waste Heat ◽  
Correct Choice ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Large Temperature ◽  
Temperature Changes ◽  
Application Range ◽  
Source And Sink

To date, research on heat pumps (HP) has mainly focused on vapour compression heat pumps (VCHP), transcritical heat pumps (TCHP), absorption heat pumps, and their heat integration with processes. Few studies have considered the Joule cycle heat pump (JCHP), which raises several questions. What are the characteristics and specifics of these different heat pumps? How are they different when they integrate with the processes? For different processes, which heat pump is more appropriate? To address these questions, the performance and integration of different types of heat pumps with various processes have been studied through Pinch Methodology. The results show that different heat pumps have their own optimal application range. The new JCHP is suitable for processes in which the temperature changes of source and sink are both massive. The VCHP is more suitable for the source and sink temperatures, which are near-constant. The TCHP is more suitable for sources with small temperature changes and sinks with large temperature changes. This study develops an approach that provides guidance for the selection of heat pumps by applying Process Integration to various combinations of heat pump types and processes. It is shown that the correct choice of heat pump type for each application is of utmost importance, as the Coefficient of Performance can be improved by up to an order of magnitude. By recovering and upgrading process waste heat, heat pumps can save 15–78% of the hot utility depending on the specific process.

DETERMINING THE PROFITABILITY OF GREENHOUSE ELECTROTECHNOLOGIES: A MODELING APPROACH

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 249a-249
Author(s):  
Eric A. Lavoie ◽  
Damien de Halleux ◽  
André Gosselin ◽  
Jean-Claude Dufour
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Water System ◽  
Heat Pumps ◽  
Hot Water ◽  
Pump System ◽  
Heat Pump System ◽  
Artificial Lighting ◽  
Hot Air ◽  
Marketable Fruit

The main objective of this research was to produce a simulated model that permitted the evaluation of operating costs of commercial greenhouse tomato growers with respect to heating methods (hot air, hot water, radiant and heat pumps) and the use of artificial lighting for 1991 and 1992. This research showed that the main factors that negatively influence profitability were energy consumption during cold periods and the price of tomatoes during the summer season. The conventional hot water system consumed less energy than the heat pump system and produced marketable fruit yields similar to those from the heat pump system. The hot water system was generally more profitable in regards to energy consumption and productivity. Moreover, investment costs were less; therefore, this system gives best overall financial savings. As for radiant and hot air systems, their overall financial status falls between that of the hot water system and the heat pump. The radiant system proved to be more energy efficient that the hot air system, but the latter produced a higher marketable fruit yield over the 2-year study.

scholarly journals Local Heating Networks with Waste Heat Utilization: Low or Medium Temperature Supply?

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 954 ◽  
Author(s):  
Hanne Kauko ◽  
Daniel Rohde ◽  
Armin Hafner
Keyword(s):  
Low Temperature ◽  
Heat Pump ◽  
Urban Areas ◽  
Waste Heat ◽  
Local Heating ◽  
District Heating ◽  
Heat Pumps ◽  
Hot Water ◽  
Local Network ◽  
Medium Temperature

District heating enables an economical use of energy sources that would otherwise be wasted to cover the heating demands of buildings in urban areas. For efficient utilization of local waste heat and renewable heat sources, low distribution temperatures are of crucial importance. This study evaluates a local heating network being planned for a new building area in Trondheim, Norway, with waste heat available from a nearby ice skating rink. Two alternative supply temperature levels have been evaluated with dynamic simulations: low temperature (40 °C), with direct utilization of waste heat and decentralized domestic hot water (DHW) production using heat pumps; and medium temperature (70 °C), applying a centralized heat pump to lift the temperature of the waste heat. The local network will be connected to the primary district heating network to cover the remaining heat demand. The simulation results show that with a medium temperature supply, the peak power demand is up to three times higher than with a low temperature supply. This results from the fact that the centralized heat pump lifts the temperature for the entire network, including space and DHW heating demands. With a low temperature supply, heat pumps are applied only for DHW production, which enables a low and even electricity demand. On the other hand, with a low temperature supply, the district heating demand is high in the wintertime, in particular if the waste heat temperature is low. The choice of a suitable supply temperature level for a local heating network is hence strongly dependent on the temperature of the available waste heat, but also on the costs and emissions related to the production of district heating and electricity in the different seasons.

Heat Integration of Absorption Heat Pump in a Milk Powder Dairy

2000 ◽  
Author(s):  
Jens Møller Andersen
Keyword(s):  
Heat Pump ◽  
Waste Heat ◽  
Cooling System ◽  
Milk Powder ◽  
Electricity Consumption ◽  
Heat Pumps ◽  
Heat Integration ◽  
Absorption Heat Pump ◽  
Absorption Cooling ◽  
Absorption Cooling System

Abstract Heat integration with absorption heat pumps requires investigation of many types of plant designs. In this article, it is concluded that in many cases high temperature absorption systems for heat recovery are more economically feasible than absorption systems for cooling purposes. The conclusion is based on a project where the scope was to investigate technical and economical possibilities for heat integration of an absorption heat pump in a milk powder plant. The first idea behind the project was to use the waste heat from the rejected air to drive an absorption cooling system to reduce the electricity consumption for cooling proposes. The model of the plant was based on simulations as a background for a time averaged COP model. It was concluded that an absorption system for generating low temperature steam is more feasible.

scholarly journals Possibility of Calcium Oxide from Natural Limestone Including Impurities for Chemical Heat Pump

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 803
Author(s):  
LanXin Lai ◽  
Toshio Imai ◽  
Motohiro Umezu ◽  
Mamoru Ishii ◽  
Hironao Ogura
Keyword(s):  
Heat Pump ◽  
Calcium Oxide ◽  
Waste Heat ◽  
Heat Pumps ◽  
Raw Material ◽  
Hydration Reaction ◽  
Chemical Heat ◽  
Chemical Heat Pump ◽  
Thermogravimetric Analyzer ◽  
Save Energy

Improving energy recycle is an important way to save energy resources and preserve the global environment. Chemical heat pump (CHP) is a technology for saving energy, which utilizes chemical reactions to store thermal energy such as waste heat and solar heat, then release it to provide heat for heating/cooling/refrigeration. For a practical CHP, it is necessary to find cheaper and more stable supply materials. In order to evaluate the possibility of calcium oxide from natural Ofunato natural limestone including impurities, we compare Ofunato limestone with Kawara natural limestone and Garou natural limestone from Japan. These calcium oxides worked as a reactant for CaO/H2O/Ca(OH)2 CHP by repeated hydration/dehydration reaction cycle experiments in a thermogravimetric analyzer. As a result, Ofunato CaO exhibits a high hydration reaction rate after decarbonization at 1223 K for 5 h. The reactivity increased by the repeated hydration reaction although the first hydration rate was low. Furthermore, the sintering of impurities in Ofunato limestone occur easier than that in Kawara limestone with lower impurities. The impurities adhered to the surface of the CaO particle to make specific surface area of CaO particle smaller, which could inhibit hydration reaction of CaO particle. Even if Ofunato limestone contains some impurities, it can be utilized as a raw material for chemical heat pumps.

Analysis of Regional Suitability of the Ground-Coupled Heat Pump Based on the Shallow Ground Thermal Balance

2009 ◽  
Author(s):  
Yuefen Gao ◽  
Songling Wang ◽  
Guoqiang Zhang
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Heat Pumps ◽  
Scientific Application ◽  
Term Operation ◽  
Ground Heat Exchangers ◽  
Ground Coupled Heat Pumps ◽  
Ground Coupled Heat Pump ◽  
Consistent Performance ◽  
Source And Sink

Ground-coupled heat pump systems use the ground as a heat source and sink either with vertical or horizontal ground heat exchangers (GHXs) to supply heating in winter and cooling in summer. The ground heat source and sink has a near constant temperature, which is well suited to ground-coupled heat pumps, giving them consistent performance, regardless of the outdoor temperature. However, when the heat extracted from and rejected to the ground has great imbalance, the ground temperature will deviate from the original temperature with a long term operation. The deviation can reduce GHX performance greatly. As China has vast territory with variety climate, the annual cooling loads and heating loads are different at different places. And the imbalance between the extracted heat and the rejected heat also varies at different places. Therefore, it is necessary to analysis the regional suitability of the ground-coupled heat pump systems. The imbalance between the extracted heat and the rejected heat is analyzed by taking several typical cities in different climates. The new concepts of the Imbalance Ratio and the Extracted Heat to Rejected Heat Ratio are introduced as the weight factors to measure the imbalance in the ground. The values of the Imbalance Ratio and those of the Extracted Heat to the Rejected Heat Ratio are calculated. The optimum range of the Imbalance Ratio is recommended based on the vast investigation of the ground-coupled heat pumps. Some supplemental systems are put forward to supply heat in winter or to reject heat in summer at the places existing serious heat imbalance. The study is very meaningful to the scientific application of the ground-coupled heat pump systems in China.

Modeling of Buoyancy-Driven Natural Ventilation in Workshop: Optimization of Distance between Heat Source and Ground

2012 ◽  
Vol 170-173 ◽  
pp. 2579-2582 ◽  
Author(s):  
Ya Xin Su ◽  
A Long Su ◽  
Xin Wan
Keyword(s):  
Heat Source ◽  
Indoor Air ◽  
Energy Cost ◽  
Lower Energy ◽  
Natural Ventilation ◽  
Waste Heat ◽  
Heat Sources ◽  
Hot Air ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Natural ventilation is suitable for application to workshops with heat sources to keep good indoor air quality at lower energy cost. In this paper, the authors numerically investigated the buoyancy-driven natural ventilation in a workshop with heat source based on computational fluid dynamics (CFD) method. The effect of the distance between heat source and ground on the air flow and temperature distribution was examined. Results showed that the average air temperature at operation zone could be effectively reduced when the distance between heat source and ground increased. The temperature field in the upper zone of the workshop was improved by diminishing the hot air zone near the ceiling and the waste heat directly going into the operation zone decreased when the distance between heat source and ground increased.

scholarly journals Air-to-air heat pump: review of recent advances and future potential

2019 ◽  
Vol 116 ◽  
pp. 00074
Author(s):  
Nicolas Serey ◽  
Darem Ahmad ◽  
Hussam Jouhara
Keyword(s):  
Heat Pump ◽  
Heat Pumps ◽  
Low Grade ◽  
Heat Sources ◽  
Energy Technology ◽  
Greenhouse Emissions ◽  
Space Cooling ◽  
Heating Water ◽  
Working Principle ◽  
Future Potential

As the demand for energy is increasing and due to more focus on the utilization of low impact energy heat sources, heat pumps are a renewable energy technology that transfers thermal energy from one place to another. Heat pumps are used in various applications such as space heating, space cooling, heating water and many others. Heat pumps have many configurations but in essence they compose of components which are found in all units. The framework for 2030 climate and energy policy has decided that greenhouse emissions must be reduced by 40%. This has therefore, increased the need to utilize low grade energy. Heat pumps have the capability to utilize the upgrade of low grade energy and reuse it within any domestic and industrial application. This paper will explain the working principle of an air-to-air heat pump, describing the different configurations, and evaluate the performance of such systems.

scholarly journals Evaluation of the Environmental Sustainability of a Stirling Cycle-Based Heat Pump Using LCA

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4469
Author(s):  
Umara Khan ◽  
Ron Zevenhoven ◽  
Tor-Martin Tveit
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
Waste Heat ◽  
Heat Pumps ◽  
Heat Output ◽  
Environmental Footprint ◽  
Stirling Cycle ◽  
Impact Reduction ◽  
Temperature Heat ◽  
Very High

Heat pumps are increasingly seen as efficient and cost-effective heating systems also in industrial applications. They can drastically reduce the carbon footprint of heating by utilizing waste heat and renewable electricity. Recent research on Stirling cycle-based very high temperature heat pumps is motivated by their promising role in addressing global environmental and energy-related challenges. Evaluating the environmental footprint of a heat pump is not easy, and the impacts of Stirling cycle-based heat pumps, with a relatively high temperature lift have received little attention. In this work, the environmental footprint of a Stirling cycle-based very high temperature heat pump is evaluated using a “cradle to grave” LCA approach. The results for 15 years of use (including manufacturing phase, operation phase, and decommissioning) of a 500-kW heat output rate system are compared with those of natural gas- and oil-fired boilers. It is found that, for the Stirling cycle-based HP, the global warming potential after of 15 years of use is nearly −5000 kg CO2 equivalent. The Stirling cycle-based HP offers an environmental impact reduction of at least 10% up to over 40% in the categories climate change, photochemical ozone formation, and ozone depletion when compared to gas- and oil-fired boilers, respectively.

scholarly journals Combining Building Renovation and Ground Source Heat Pump Installations for the Reduction of Greenhouse Gas Emissions: A Case Study in Vaasa Finland

2009 ◽  
Vol 4 (1) ◽  
pp. 146-168
Author(s):  
Joyce Cooper ◽  
Tarja Häkkinen ◽  
Sirje Vares ◽  
Jenni Jahn ◽  
Sakari Pulakka
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Heat Pump ◽  
Heat Pumps ◽  
Heat Sources ◽  
Ground Source Heat Pump ◽  
Ground Source Heat Pumps ◽  
Gas Emissions ◽  
Ground Source

Given the growing interest in ground source heat pump and distributed heating installations in general for the reduction of greenhouse gas emissions, technology implementation planning can benefit from the simultaneous consideration of building renovations. Here, a method for identifying and evaluating scenarios based on cost and greenhouse gas emissions is presented. The method is demonstrated for a case study in Vaasa Finland. The case study considers the insulation of the walls, roof, and base floor and the replacement of windows based on 2003 and 2010 Finnish building codes simultaneously with the possible replacement of existing heat sources with ground source heat pumps. Estimates of changes in heat demand for consecutive renovations are combined with data on renovation, installation, heating costs, and life cycle greenhouse gas emissions data for the current and proposed heat sources. Preferred scenarios are identified and evaluated by building type, construction decade, and current heating source. The results are then placed within the contexts of the Vaasa building stock and policy theory.

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