scholarly journals Thermo-Chemical Instability and Energy Analysis of Absorption Heat Pumps

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1966
Author(s):  
Gábor L. Szabó
Keyword(s):  
Heat Pump ◽  
Energy Demand ◽  
Energy Analysis ◽  
Heat Pumps ◽  
Condensation Temperature ◽  
Heat Sources ◽  
Evaporation And Condensation ◽  
Chemical Instability ◽  
Heating And Cooling ◽  
Points Of View

This paper presents the results of energy analysis of absorption heat pumps. The thermo-chemical instability term was introduced for absorption heat pumps used for heating or cooling or heating and cooling. A higher thermo-chemical instability results in the equipment being more sensitive with regard to the variation of the heat source flux. This sensitivity can be taken into account when heat sources are chosen for a certain absorption machine. Absorption heat pumps having thermo-chemical compressors were compared from energy demand and energy efficiency points of view with heat pumps having mechanical compressors. As it is shown, for certain evaporation and condensation temperature values, an absorption heat pump with similar efficiency to that of the heat pump with a mechanical compressor can always be found.

scholarly journals A European Database of Building Energy Profiles to Support the Design of Ground Source Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2496 ◽  
Author(s):  
Laura Carnieletto ◽  
Borja Badenes ◽  
Marco Belliardi ◽  
Adriana Bernardi ◽  
Samantha Graci ◽  
...  
Keyword(s):  
Heat Pump ◽  
Energy Demand ◽  
Residential Buildings ◽  
Building Energy ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Energy Profiles ◽  
Ground Source

The design of ground source heat pumps is a fundamental step to ensure the high energy efficiency of heat pump systems throughout their operating years. To enhance the diffusion of ground source heat pump systems, two different tools are developed in the H2020 research project named, “Cheap GSHPs”: A design tool and a decision support system. In both cases, the energy demand of the buildings may not be calculated by the user. The main input data, to evaluate the size of the borehole heat exchangers, is the building energy demand. This paper presents a methodology to correlate energy demand, building typologies, and climatic conditions for different types of residential buildings. Rather than envelope properties, three insulation levels have been considered in different climatic conditions to set up a database of energy profiles. Analyzing European climatic test reference years, 23 locations have been considered. For each location, the overall energy and the mean hourly monthly energy profiles for heating and cooling have been calculated. Pre-calculated profiles are needed to size generation systems and, in particular, ground source heat pumps. For this reason, correlations based on the degree days for heating and cooling demand have been found in order to generalize the results for different buildings. These correlations depend on the Köppen–Geiger climate scale.

scholarly journals Energy Analysis of a Dual-Source Heat Pump Coupled with Phase Change Materials

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2933
Author(s):  
Michele Bottarelli ◽  
Francisco Javier González Gallero
Keyword(s):  
Phase Change ◽  
Heat Pump ◽  
Energy Demand ◽  
Phase Change Materials ◽  
Weather Conditions ◽  
Heat Pumps ◽  
Ground Heat Exchangers ◽  
Heating And Cooling ◽  
Air Source Heat Pump ◽  
Dual Source

Installation costs of ground heat exchangers (GHEs) make the technology based on ground-coupled heat pumps (GCHPs) less competitive than air source heat pumps for space heating and cooling in mild climates. A smart solution is the dual source heat pump (DSHP) which switches between the air and ground to reduce frosting issues and save the system against extreme temperatures affecting air-mode. This work analyses the coupling of DSHP with a flat-panel (FP) horizontal GHE (HGHE) and a mixture of sand and phase change materials (PCMs). From numerical simulations and considering the energy demand of a real building in Northern Italy, different combinations of heat pumps (HPs) and trench backfill material were compared. The results show that PCMs always improve the performance of the systems, allowing a further reduction of the size of the geothermal facility. Annual average heat flux at FP is four times higher when coupled with the DSHP system, due to the lower exploitation. Furthermore, the enhanced dual systems are able to perform well during extreme weather conditions for which a sole air source heat pump (ASHP) system would be unable either to work or perform efficiently. Thus, the DSHP and HGHE with PCMs are robust and resilient alternatives for air conditioning.

scholarly journals Heat pump systems: A mini review

2021 ◽  
Vol 4 (2) ◽  
pp. 73-81
Author(s):  
Mohammad Omar Temori ◽  
František Vranay
Keyword(s):  
Heat Pump ◽  
Electricity Consumption ◽  
Cost Savings ◽  
Electrical Energy ◽  
Primary Energy ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Heating And Cooling ◽  
Ground Source ◽  
Reduce Electricity Consumption

In this work, a mini review of heat pumps is presented. The work is intended to introduce a technology that can be used to income energy from the natural environment and thus reduce electricity consumption for heating and cooling. A heat pump is a mechanical device that transfers heat from one environmental compartment to another, typically against a temperature gradient (i.e. from cool to hot). In order to do this, an energy input is required: this may be mechanical, electrical or thermal energy. In most modern heat pumps, electrical energy powers a compressor, which drives a compression - expansion cycle of refrigerant fluid between two heat exchanges: a cold evaporator and a warm condenser. The efficiency or coefficient of performance (COP), of a heat pump is defined as the thermal output divided by the primary energy (electricity) input. The COP decreases as the temperature difference between the cool heat source and the warm heat sink increases. An efficient ground source heat pump (GSHP) may achieve a COP of around 4. Heat pumps are ideal for exploiting low-temperature environmental heat sources: the air, surface waters or the ground. They can deliver significant environmental (CO2) and cost savings.

scholarly journals A GIS-Based Planning Approach for Urban Power and Natural Gas Distribution Grids with Different Heat Pump Scenarios

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4052 ◽  
Author(s):  
Jolando M. Kisse ◽  
Martin Braun ◽  
Simon Letzgus ◽  
Tanja M. Kneiske
Keyword(s):  
Co2 Emissions ◽  
Heat Pump ◽  
Energy Demand ◽  
Low Voltage ◽  
Primary Energy ◽  
Heat Pumps ◽  
Slight Reduction ◽  
Single Family ◽  
Gas Distribution ◽  
Public Data

Next to building insulation, heat pumps driven by electrical compressors (eHPs) or by gas engines (geHPs) can be used to reduce primary energy demand for heating. They come with different investment requirements, operating costs and emissions caused. In addition, they affect both the power and gas grids, which necessitates the assessment of both infrastructures regarding grid expansion planning. To calculate costs and CO2 emissions, 2000 electrical load profiles and 180 different heat demand profiles for single-family homes were simulated and heat pump models were applied. In a case study for a neighborhood energy model, the load profiles were assigned to buildings in an example town using public data on locations, building age and energetic refurbishment variants. In addition, the town’s gas distribution network and low voltage grid were modeled. Power and gas flows were simulated and costs for required grid extensions were calculated for 11% and 16% heat pump penetration. It was found that eHPs have the highest energy costs but will also have the lowest CO2 emissions by 2030 and 2050. For the investigated case, power grid investments of 11,800 euros/year are relatively low compared to gas grid connection costs of 70,400 euros/year. If eHPs and geHPs are combined, a slight reduction of overall costs is possible, but emissions would rise strongly compared to the all-electric case.

Solar-Assisted Heat Pump Systems: A Review of Existing Studies and Their Applicability to the Canadian Residential Sector

2013 ◽  
Author(s):  
Jenny Chu ◽  
Cynthia A. Cruickshank
Keyword(s):  
Heat Pump ◽  
Residential Buildings ◽  
International Energy Agency ◽  
Heat Pumps ◽  
Hot Water ◽  
Performance Criteria ◽  
Space Heating ◽  
Residential Sector ◽  
Heating And Cooling ◽  
System Configurations

Heat pumps are commonly used for space-heating and cooling requirements. The combination of solar thermal and heat pump systems as a single solar-assisted heat pump (SAHP) system is a promising technology for offsetting domestic hot water, space-heating and cooling loads more efficiently. Task 44 of the Solar Heating and Cooling Programme of the International Energy Agency is currently investigating ways to optimize SAHP systems for residential use. This paper presents a review of past and current work conducted on SAHP systems. Specifically, the key performance data from many studies are highlighted and different system configurations are compared in order to establish insight towards which system configurations are suitable for the Canadian residential sector. It was found that the most suitable configuration for Canadian residential buildings depend on a combination of factors which may include occupant behavior, building characteristics, operation parameters, system components, the performance criteria of interest and climate. A large variety of configurations and parameters exist for SAHP systems and this made analyzing a specific system, comparing differing systems and establishing an optimal design fairly difficult. It was found that different authors used various different performance criterions and this inconsistency also added to the difficulty of comparing the studies of different systems. Overall, a standard performance criterion needs to be established for SAHP systems in order to meaningfully compare different configurations and determine optimal configurations for certain requirements.

scholarly journals Modeling of an Air Conditioning System with Geothermal Heat Pump for a Residential Building

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Silvia Cocchi ◽  
Sonia Castellucci ◽  
Andrea Tucci
Keyword(s):  
Heat Pump ◽  
Air Conditioning ◽  
Residential Building ◽  
Heat Pumps ◽  
Geothermal Heat ◽  
Air Conditioning System ◽  
Heating And Cooling ◽  
Ground Source ◽  
Geothermal Heat Pump ◽  
Geothermal Plant

The need to address climate change caused by greenhouse gas emissions attaches great importance to research aimed at using renewable energy. Geothermal energy is an interesting alternative concerning the production of energy for air conditioning of buildings (heating and cooling), through the use of geothermal heat pumps. In this work a model has been developed in order to simulate an air conditioning system with geothermal heat pump. A ground source heat pump (GSHP) uses the shallow ground as a source of heat, thus taking advantage of its seasonally moderate temperatures. GSHP must be coupled with geothermal exchangers. The model leads to design optimization of geothermal heat exchangers and to verify the operation of the geothermal plant.

scholarly journals Performance Indexes of an Air-Water Heat Pump Versus the Capacity Ratio: Analysis by Means of Experimental Data

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3391
Author(s):  
Roberto Bruno ◽  
Francesco Nicoletti ◽  
Giorgio Cuconati ◽  
Stefania Perrella ◽  
Daniela Cirone
Keyword(s):  
Heat Pump ◽  
Storage System ◽  
Heat Pumps ◽  
Technical Standards ◽  
Capacity Ratio ◽  
Heating And Cooling ◽  
Performance Indexes ◽  
Real Performance ◽  
Using Data ◽  
Set Up

The spread of near-Zero Energy Buildings (nZEB) involves the employment of high performant air-conditioning plants where renewable sources can be integrated easily. In this context, heat pumps appear as a promising solution given their ability to exploit aerothermal, hydrothermal and geothermal sources and to supply both heating and cooling loads with the same device. In order to evaluate the energy performances in transient conditions, the actual winter (COP) and summer (EER) performance indexes, in the function of the sources’ temperatures and the capacity ratio (CR), have to be available. Nevertheless, heat pump manufactures often provide the trend of the performance indexes in the function of the temperatures of the sources specifically for nominal conditions, whereas the dependence of the performance indexes in the function of CR, that takes into account the part-load operation, is almost always not provided. Alternatively, specific technical standards suggest the use of a correction factor to modify nominal COP and EER for the attainment of the real performance indexes. In this paper, by using data from an experimental set-up equipped with air-water heat pumps, these correlations were tested and tuned. Winter results showed that correction factors suggested by standards have to be modified in the presence of a storage system. In summer, instead, a new correlation was developed to find a function between nominal and actual EERs in the function of CR by exploiting a similar approach employed for the COP calculation.

scholarly journals Integration of Reversible Heat Pumps in Trigeneration Systems for Low-Temperature Renewable District Heating and Cooling Microgrids

2019 ◽  
Vol 9 (15) ◽  
pp. 3194 ◽  
Author(s):  
Urbanucci ◽  
Testi ◽  
Bruno
Keyword(s):  
Low Temperature ◽  
Carbon Dioxide Emissions ◽  
Energy Demand ◽  
Water Distribution ◽  
District Heating ◽  
Energy System ◽  
Heat Pumps ◽  
Energy Technologies ◽  
Heating And Cooling ◽  
Viable Solution

District heating and cooling networks based on trigeneration systems and renewable energy technologies are widely acknowledged as an energy efficient and environmentally benign solution. These energy systems generally include back-up units, namely fossil-fuel boilers and electric chillers, to enhance system flexibility and cover peak energy demand. On the other hand, 4th generation district heating networks are characterized by low-temperature water distribution to improve energy and exergy efficiencies. Moreover, reversible heat pumps are a versatile technology, capable of providing both heating and cooling, alternately. In this paper, the integration of reversible heat pumps as single back-up units in hybrid renewable trigeneration systems serving low-energy micro-district heating and cooling networks is investigated. A detailed modeling of the system is provided, considering part-load and ambient condition effects on the performance of the units. Size and annual operation of the proposed system are optimized in a case study, namely a large office building located in Pisa (Italy), by means of a genetic algorithm-based procedure. A comparison with the conventional trigeneration system is performed in terms of economic and environmental perspectives. Results show that the integration of reversible heat pumps is an economically viable solution capable of reducing by 7% the equivalent annual cost, increasing the installed power of renewables up to 23%, and lowering by 11% carbon dioxide emissions, compared to the energy system with conventional back-up units.

scholarly journals PVT and ETC Coupling for Annual Heating and Cooling by Absorption Heat Pumps

2020 ◽  
Vol 12 (17) ◽  
pp. 7042
Author(s):  
Marco Noro ◽  
Renato Lazzarin
Keyword(s):  
Heat Pump ◽  
Cell Damage ◽  
Primary Energy ◽  
Heat Pumps ◽  
Solar Thermal ◽  
Solar Collectors ◽  
Absorption Chiller ◽  
Heating And Cooling ◽  
Cold Source ◽  
Temperature Levels

Until recently, solar assisted heat pumps have used solar collectors as a cold source. Solar collectors provide, when possible, direct heat, otherwise they offer temperature levels to the heat pump evaporator higher than the outside air. At the same time, solar thermal cooling exploits the solar collectors and the absorption chiller only in hot months. Photovoltaic/Thermal (PVT) modules have been available on the market in recent years for solar cogeneration, but their utilization can be problematic due to PhotoVoltaic (PV) cell damage in cases where there is no heating request. This paper considers the possibility of coupling evacuated tube collectors and photovoltaic/thermal modules to drive an absorption heat pump-based plant operating as an absorption chiller in the summertime. The cold source is the solar energy and the ground, which is recharged by the solar thermal and photovoltaic/thermal collectors and by the cooling of the absorber-condenser in mid-seasons and summer. This study analyzes the system behavior in yearly operation and evaluates the role of suitable storage tanks in two different climates, varying the size of the two solar fields and the generator tank. In the best plant configuration, a primary energy ratio of 26.6 in colder climates with cloudy skies and 20 in hotter climates with clearer skies is obtained.

scholarly journals A Review of Heat Pump Systems and Applications in Cold Climates: Evidence from Lithuania

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4331 ◽  
Author(s):  
Rokas Valancius ◽  
Rao Martand Singh ◽  
Andrius Jurelionis ◽  
Juozas Vaiciunas
Keyword(s):  
Heat Pump ◽  
Energy Demand ◽  
New Technologies ◽  
Technology Development ◽  
Good Practice ◽  
Cost Benefit ◽  
Water Source ◽  
Heat Pumps ◽  
Cold Climate ◽  
Hot Water

Similar to other cold climate countries, space heating and domestic hot water (DHW) accounts form the largest share of household energy demand in Lithuania. Heat pump technology is considered to be one of the environmentally friendly solutions to increase energy efficiency and reduce the carbon footprint of buildings. Heat pumps have been finding their way into the Lithuanian market since 2002, and currently there are many good practice examples present in the country, especially in the residential and public sectors. Heat pump use is economically advantageous in the Baltic Region, and the market share of these systems is growing. Studies have reported seasonal performance factor (SPF) ranges within 1.8 and 5.6. The lower SPF values are typically attributable to air source heat pumps, whereas the higher efficiency is achieved by ground or water source heat pump applications. While the traditional heat pump techniques are well established in the region, there is a slow uptake of new technologies, such as solar-assisted heat pumps, absorption heat pumps and heat pumps integrated into foundations, tunnels or diaphragm walls. This paper provides a critical review of different heat pump technologies, using Lithuania as a cold climate case study to overview the market trends within the European context. Potential trends for the heat pump technology development in terms of application areas, cost-benefit predictions, as well as environmental aspects, are discussed.

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