| 1. |
- Beltran, Francisco, et al.
(författare)
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Solar Heat Pumps and Self-Consumption Can (and should) electricity suppliers encourage thermal storage?
- 2022
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Ingår i: 2022 BuildSim Nordic, BSN 2022. - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- Heat pumps and water tanks can be used to increase PV self-consumption in buildings without any additional equipment, but there is sometimes a lack of economic incentives to maximize it that limits economic gains. Therefore, pricing conditions need to change in order to make self-consumption strategies more interesting for prosumers. This study aims at determining what, if any, unsubsidized market conditions could lead to economically motivated self-consumption control strategies with solar heat pumps. A sensitivity analysis is used on multiple pricing models based on current market conditions for a solar PV and ground source heat pump system for a single-family house in Norrköping, Sweden. The results show that control strategies aimed at maximizing self-consumption have very little impact on net costs, regardless of pricing model or variation in price. Feed-in-bonus is the most important aspect when comparing different pricing schemes, and no other sensitivity comes close.
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| 2. |
- Caramaschi, Matteo, et al.
(författare)
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Natural refrigerant mixtures in low-charge heat pumps: An analysis of the potential for performance enhancements
- 2024
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Ingår i: International journal of refrigeration. - : Elsevier BV. - 0140-7007 .- 1879-2081. ; 165, s. 70-83
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Tidskriftsartikel (refereegranskat)abstract
- The study investigated the characteristics of different natural refrigerants and their mixtures in a residential heat pump with low refrigerant charge. Three main evaluation criteria were utilized for comparing different mixtures: Coefficient of Performance (COP), Volumetric Heating Capacity (VHC), and a newly proposed indicator, the heating capacity at charge limit. Propane was used as a reference refrigerant. It was found that some mixtures significantly improved both COP and the heating capacity at charge limit while maintaining similar volumetric heating capacity and operating conditions. Alternative multi-criteria decision-making techniques were adopted to rank the best refrigerant mixtures. Mixtures rich in Dimethyl Ether (DME), such as DME-CO2 [0.96-0.04] and DME-Propylene [0.75-0.25] were found consistently among the best options. Those were followed by Propylene-rich mixtures such as Propylene-CO2, Propylene-Isobutane and Propylene-Butane. The levelized cost of heat (LCOH) could be improved by up to 12 %. To accelerate the transition to natural refrigerants, without compromises on efficiency and costs, further research and certification activities on non-fluorinated refrigerants based on Dimethyl Ether (R-E170), CO2 (R-744) and Propylene (R-1270) are recommended.
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| 3. |
- Fischer, David, et al.
(författare)
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Model-based flexibility assessment of a residential heat pump pool
- 2017
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 118, s. 853-864
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents and demonstrates a methodology to explore the flexibility of a heat pump pool. Three points are in the focus of this work: First the procedure to model a pool of residential heat pump systems. Second the study of the response of a large number of heat pumps when the Smart-Grid-Ready interface is used for direct load control. Third a general assessment of flexibility of a pool of heat pump systems. The presented pool model accounts for the diversity in space heating and domestic hot water demands, the types of heat source and heat distribution systems used and system sizing procedures. The model is validated using field test data. Flexibility is identified by sending trigger signals to a pool of 284 SG-Ready heat pumps and evaluating the response. Flexibility is characterized by maximum power, shiftable energy and regeneration time. Results show that flexibility is highly dependent on the ambient temperature and the use of an electric back-up heater. It is found that using SG-Ready-like signals offers significantly higher flexibility than just switching off heat pumps, as it is mostly done today.
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| 4. |
- Fischer, D., et al.
(författare)
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Smart meter enabled control for variable speed heat pumps to increase PV self-consumption
- 2015
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Ingår i: Refrigeration Science and Technology. - : International Institute of Refrigeration. - 9782362150128 ; , s. 4049-4056
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Konferensbidrag (refereegranskat)abstract
- In the last five years the costs of photovoltaic systems have decreased considerably making it economically attractive to generate electricity locally. In many countries, self-consumption is the most attractive option to make use of the generated electricity. Variable speed heat pumps - if controlled properly - can take a share of the PV electricity to decrease costs and CO2 emissions for heat generation and increase PV self-consumption. This paper discusses a control strategy that uses real-time smart meter readings and adjusts the compressor speed to adapt heat pump electricity consumption depending on the available PV power. The approach is tested in a detailed building simulation. Self-consumption can be increased by 6% compared to a heat driven control. For the chosen PV size of 10kWp in a German multi-family house, an increase of storage size shows only little possibility for a further increase in self-consumption.
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| 5. |
- Francisco, Beltrán, et al.
(författare)
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Empirical investigation of solar photovoltaic-thermal collectors for heat pump integration
- 2024
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311 .- 1873-5606. ; 248
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Tidskriftsartikel (refereegranskat)abstract
- This study empirically investigates the optimal design features of photovoltaic-thermal (PVT) collectors for integration with ground source heat pump (GSHP) systems, considering technical and economic factors. Outdoor experiments are conducted in Stockholm, Sweden, comparing five unglazed and uninsulated PVT collector designs a) Reference Sheet & Tube b) Sheet & Tube with a narrow air gap between PV and absorber plate c) Box-channel polypropylene d) Finned tube and e) Box-channel aluminum with fins at operating temperatures below ambient. The findings indicate that the box-channel aluminum design with fins, characterized by a superior combination of high zero-loss efficiency and a high U-value, emerges as the ideal PVT design for integration with ground source heat pumps, taking into account both technical and economic considerations. Despite having a relative specific thermal cost 9% higher than the reference collector, this design demonstrates the capability to generate 2,096 kWh/(m2a) of thermal energy, marking an 83.3% increase compared to the reference, with a 136% higher energy-to-mass ratio.
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| 6. |
- Hesaraki, Arefeh, PhD, 1987-, et al.
(författare)
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Energy Performance of Ground-source Heat Pump and Photovoltaic/thermal (PV/T) in Retrofitted and New Buildings : Two Case Studies Using Simulation and On-site Measurements
- 2020
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Konferensbidrag (refereegranskat)abstract
- This paper aims to contribute by presenting calculated and measured electricity usage in two single-family case studies during the heating season of 2019-2020 located in Stockholm, Sweden. The electricity usage included consumption by heat pumps’ compressor to cover space heating and domestic hot water, auxiliary energy for fans and pumps, and ventilation system. The first case study was built in 1936 with an oil burner, which was renovated to a ground-source heat pump (GSHP) in 2015, and the second case study was a new building built in 2013 with a GSHP. The application of photovoltaic/thermal (PVT) systems in combination with GSHP was theoretically investigated for both case studies. Buildings were modelled using the energy simulation tool IDA Indoor Climate and Energy (ICE), and the model was validated against the measured electrical energy usage. PVT was designed to balance the maximum heat production with domestic hot water consumption during the summer months. Simulation results revealed that combining GSHP with 5 m2 grid-connected PVT gave 21% and 22% energy savings in case study 1 and case study 2, respectively. Employing a battery storage to store extra electricity production by PVT increased the energy savings to 24 % and 32 % for case study 1 and case study 2, respectively. Moreover, in both cases approximately half of the total annual domestic hot water need was prepared by 5 m2 PVT.
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| 7. |
- Madani Larijani, Hatef, et al.
(författare)
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Capacity control in ground source heat pump systems Part I : modeling and simulation
- 2011
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Ingår i: International journal of refrigeration. - : Elsevier BV. - 0140-7007 .- 1879-2081. ; 34:6, s. 1338-1347
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Tidskriftsartikel (refereegranskat)abstract
- The present paper, as the first part of two, suggests a method to approach the challenge of capacity control in Ground Source Heat Pumps (GSHP). The paper describes the development of a model of the system which includes several sub-models such as the heat pump unit, building, ground source, thermal storage tank, auxiliary heater, and climate. The developed computer model can be used for comparative analysis of different control methods and strategies aiming at the improvement of the system seasonal performance. With this model, on/off controlled and variable capacity GSHPs, with a single speed or variable speed pumps in the systems, can be evaluated in a wide range of operating conditions and more energy efficient methods of the system control can be found. The computer model is developed in the two environments EES and TRNSYS utilizing so-called co-solving technique.
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| 8. |
- Pressani, Michele, et al.
(författare)
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Investigation Of Pv/Thermal Collector Models For Use With Ground Source Heat Pumps In Transient Simulations
- 2017
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Ingår i: PROCEEDINGS OF THE 11TH ISES EUROSUN 2016 CONFERENCE. - Freiburg, Germany : International Solar Energy Society. ; , s. 1360-1371
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Konferensbidrag (refereegranskat)abstract
- Photovoltaic-thermal (PVT) collectors are commonly designed for use in domestic hot water systems, however it can be interesting to incorporate them into ground source heat pump (GSTIP) systems. Because of the historically narrow use case, many PVT models are created with a collection of assumptions which may not apply to novel collectors designed for use in PVT+GSHP systems. The aims of this study are to review existing PVT collector models for use in TRNSYS, identify any potential error sources, and test for possible improvements. Type 560 is found to be the most promising theoretical model, however two potentially limiting features are identified; the radiation absorption model and the confinement to sheet-and-tube configurations. The absorption is tested using a recreation of Type 560 in Matlab where two alternative models developed specifically for PV modules are compared. The results show a marked increase in power during low angle, low light hours, and a 14.36% increase in electrical energy and a 10.91% for the thermal energy over the course of a day with one of the models. Collector geometry is tested by creating a ID model in EES and comparing it to several geometries in Type 560. A method of packing as many tubes as possible together is shown to give comparable results as the ID model. The results of these simulations will be compared with empirical data from currently ongoing testing.
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| 9. |
- Schreurs, Twan, et al.
(författare)
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Techno-economic analysis of combined heat pump and solar PV system for multi-family houses : An Austrian case study
- 2021
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Ingår i: Energy Strategy Reviews. - : Elsevier BV. - 2211-467X .- 2211-4688. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- With the increasing amount of building renovations in Austria, the potential increases for replacing conventional national gas heating systems with heat pumps (HP) and thereby reduce CO2 emissions particularly when combined with solar photovoltaics (PV). The Austrian subsidization scheme for HP and PV systems are different for every state, creating confusion and inconstancy for potential adopters. This study provides a parametric technoeconomic analysis of PV + HP systems to identify the critical economic parameters on profitability and make policy recommendations. A case study in Vienna is modelled using demand from the Building Model Generator and black box efficiency models for the HP and PV simulated with hourly time steps. The results show that both air-source and ground source heat pumps are currently profitable with PV under current subsidy schemes. The benefit-to-cost ratio (BCR) is highly influenced by capital costs and subsidies, however natural gas prices have the greatest influence. Increasing natural gas prices by 0.01 euro/kWh, or 17%, is enough to replace all other complicated subsidies for both HP and PV. This is equivalent to a carbon emissions price of 33 euro/ton and could result in a reduction of CO2 emissions in multi-family houses by approximately 45%-60%.
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| 10. |
- Shahcheraghian, Amir, et al.
(författare)
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From White to Black-Box Models : A Review of Simulation Tools for Building Energy Management and Their Application in Consulting Practices
- 2024
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 17:2
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Forskningsöversikt (refereegranskat)abstract
- Buildings consume significant energy worldwide and account for a substantial proportion of greenhouse gas emissions. Therefore, building energy management has become critical with the increasing demand for sustainable buildings and energy-efficient systems. Simulation tools have become crucial in assessing the effectiveness of buildings and their energy systems, and they are widely used in building energy management. These simulation tools can be categorized into white-box and black-box models based on the level of detail and transparency of the model’s inputs and outputs. This review publication comprehensively analyzes the white-box, black-box, and web tool models for building energy simulation tools. We also examine the different simulation scales, ranging from single-family homes to districts and cities, and the various modelling approaches, such as steady-state, quasi-steady-state, and dynamic. This review aims to pinpoint the advantages and drawbacks of various simulation tools, offering guidance for upcoming research in the field of building energy management. We aim to help researchers, building designers, and engineers better understand the available simulation tools and make informed decisions when selecting and using them.
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