Large Air-to-Water Heat Pumps for Fuel-Boiler Substitution in Non-Retrofitted Multi-Family Buildings—Energy Performance, CO2 Savings, and Lessons Learned in Actual Conditions of Use
Abstract
:1. Introduction
1.1. Context and Issues
1.2. Heat Pump Market
1.3. Monitoring
1.4. Simulations
1.5. Environmental Indicators
1.6. Objectives of This Study
- What actual performance can we expect from ASHP systems in large non-retrofitted MFBs?
- What are the potential constraints and issues of such systems, namely in terms of monovalent versus hybrid HPs, as well as large industrial HP units versus bundled standardized small HP units?
- What are the renewable energy fraction and the actual CO2eq savings based on the actual hourly Swiss electricity mix?
2. Description
2.1. Monitorited Buildings
- Project 1 (monovalent HP system): This building was constructed in 1972, during the baby-boom period, and it is characterized by a cheap structure and a poor envelope quality. It has a heated floor area of 4047 m2 (7 floors), and its envelope has not undergone any retrofit.
- Project 2 (hybrid HP system): This building was built in 1992 during a construction boom, using a pre-fabricated envelope. It has a total heated floor area of 7563 m2 (5 floors), and its thermal envelope has not been renovated.
2.2. ASHP System
2.2.1. Monovalent ASHP System
2.2.2. Hybrid ASHP System
- -
- In SH mode, the 6 HP units are bundled in 2 groups, each composed of a master HP controlling two slave HPs (which is the maximum number of slaves the internal regulation of these master HPs can handle). Optimal heat production in relation with SH load is provided by the internal regulation of each master HP, which controls cascading of the three related units (according to the actual SH distribution temperature, related to the SH heating curve). The master of the first HP group (dedicated to SH) also controls complementary on/off switching of the boiler, with a parametrizable time delay.
- -
- In DHW mode, the 3 dedicated HP units operate independently from each other (no integrated master/slave operation available). A “manual” cascade is induced by way of distinct temperature setpoints for on/off switching in relation to the temperature of the HP storage tank (common upper setpoint for HP switch off, distinct lower setpoints for each HP switch on). In the absence of an integrated master/slave operation mode, complementary on/off switching of the boiler is activated by a mechanical thermostat.
3. Methodology
3.1. Monitoring
3.2. Performance Indicators
3.2.1. Energy Performance
3.2.2. Environmental Performance
4. Results—Monovalent System
4.1. Annual Energy Balance, CO2 Emissions, and Renewable Energy Fraction
4.2. Heat Demand and Production
- -
- In SH mode: during the first year of operation, the SH production temperature always remained above 50 °C, not taking into account the heating curve defined at the level of the centralized automation; the latter was fixed for the second year, during which the heating curve was also was reduced by approximately 5 K.
- -
- In DHW mode: during the second year, adjustments in the DHW setpoint also helped to decrease the distribution temperature, and hence the HP production, by about 3–5 K each.
4.3. HP Capacity and Heat Load
4.4. ASHP Performance
- -
- During this period, one of the ASHP had its circulation pump constantly activated, even when the production was off. This error caused an electricity overconsumption of 72 kWhelec/day without production, which degraded the from 2.1 to 1.5 during summer 2018. This overconsumption represents 31% of the ASHP system’s daily electricity consumption in summer. It becomes less important in the winter (5%).
- -
- In the case of DHW production, the large flowrate in the ASHPs as compared to the one in the DHW heat exchangers (see Section 2.2.1) resulted in high return temperatures to the ASHPs, which reduced their performance. The problem was eventually solved by letting the entire flow from the ASHP circulate through the heat exchangers.
5. Results—Hybrid System
5.1. Annual Energy Balance, CO2 Emissions, and Renewable Energy Fraction
5.2. Heat Demand and Production
- -
- In SH mode: during the first year of operation, the system suffered several HP shutdowns when the boiler was activated, caused by high SH return temperatures being directed to the HP storage tank (see Figure 5), which in turn was causing high-pressure alarms on the HPs. The problem was eventually solved by: (i) implementation of a three-way valve on the SH return flow which, when the SH return temperature is too high for the HP, is now redirected towards the boiler instead of the HP storage tank; (ii) increased delay for boiler switch-on, leaving more time for the HPs to operate in stand-alone mode.
- -
- In DHW mode: during the first year of operation, the “manual” cascading of the 3 dedicated HPs was causing a slow thermal response of the storage tank, leading to complementary switch on of the boiler for reaching of the desired DHW temperature. The problem could eventually be solved by defining identical on/off setpoints in each HP, getting rid of the cascading effect (all 3 HPs switched on and off at the same time), reducing the thermal response of the storage. However, this adjustment induces shorter and numerous HP on/off cycles, which reduces the life expectancy of the machine and decreases the performance, as shown in several studies [46,47].
- -
- At the beginning of the second heating season, in November 2018, SH is provided only by the boiler, due to a manual valve which remained closed, preventing heat distribution by the HPs. Between March and April 2019, SH is again provided only by the boiler, due to a breakdown of the HPs.
- -
- In SH mode: during the second year of operation, the heating curve was limited to a maximum of 50 °C, compatible with the maximum HP production temperature of 55 °C, so that the boiler had to not be activated for insufficient temperature, but only for missing capacity.
- -
- In DHW mode: during the second year, adjustments in the setpoints allowed to increase the HP production temperature and reduce the temperature of the boiler, contributing to an increase of the HP share in DHW production.
5.3. HP Capacity and Heat Load
5.4. ASHP Performance
6. Discussion
6.1. Synthetic Comparison of the Case Studies
6.2. Issues Identified
- -
- Monovalent system: The two industrial ASHP models are able to fully supply the current heat demand of the non-retrofitted MFB, however the following issues which occurred during the first year of monitoring had to be solved: (i) internal setpoints of the industrial ASHP, which were not considering the heating curve defined at the level of the centralized automation; (ii) constantly activated circulation pumps, even when the production was off; (iii) high return temperatures to the ASHP, due to incompatibilities between HP units and DHW heat exchanger; (iv) HP breakdown during an entire month, due to lack of a trained technician who ultimately came from another region of the country.
- -
- Hybrid system: Compared to the monovalent project, this project has a high level of complexity in terms of hydraulic concept and regulation, since it was necessary to combine the operation of smaller ASHP units in cascade, along with the old existing boiler. Several types of malfunctioning were identified and solved: (i) high return temperatures causing heat pump failures when operating in parallel with the boiler; (ii) limited master-slave control and related cascade of HP units and boiler; (iii) heat losses in the pipes connecting the ASHP located on the roof to the boiler room. Furthermore, residents of an apartment on the top floor of the building reported excessive noise from the HP, which could be heard from open windows. This was confirmed acoustic measurements, after which the air inlets and outlets of the heat pumps were equipped with adequate sound absorbers.
7. Conclusions
- -
- Monovalent systems are in principle easier to integrate and to regulate, in particular regarding interaction between HPs and boiler and related operating temperatures. They are, however, easily subject to oversizing (and related overinvestment), due to the targeted 100% share. The latter raises the question whether to consider “monovalent” HP systems with direct electric heating for extreme peak loads. This should be further analyzed in terms of the related energy mix, grid connection capacities, as well as cost aspects.
- -
- Besides a comparative advantage in terms of cost and space, hybrid systems represent a flexible option for existing buildings, in view of forthcoming retrofit and the related decrease of heat load.
- -
- Large industrial HPs need less space and hydraulics, with the complementary advantage of reduced heat losses, but they currently require specific constructive measures in terms of noise reduction and possibly for structural reasons linked to their weight.
- -
- Bundling of small HPs developed for the SFB market offers an advantage regarding weight distribution on the roof. Currently (at least based on this project), their integrated control systems are not yet suitable for integrating a large number of units and their production temperature does not always meet the requirements.
- Sensitivity analysis by way of numerical simulation, in order to derive robust sizing and integration rules.
- Specific focus on control strategies and cascading, with the objective of robust and flexible control strategies for heat pump manufacturers and engineering firms.
- Alternative and/or complementary system integration, i.e., by combination of heat pump systems with photovoltaics (PV) or hybrid photovoltaic thermal solar collector (PV-T).
- Optimal/flexible strategies for combined fuel-switch and envelope-retrofit, in terms of energy performance, CO2 savings, cost, and architectural constraints.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
Nomenclature
Acronyms | |
ASHP | Air-Source Heat Pump |
DHN | District Heating Network |
DHW | Domestic Hot Water |
HDD | Heating Degree Days |
HP | Heat Pump |
MFB | Multi-Family Buildings |
SFB | Single Family Buildings |
SH | Space Heating |
Symbols | |
Annual emissions from HP electricity consumption (kgCO2eq) | |
Annual emissions from boiler consumption (kgCO2eq) | |
Annual total emissions of the system from electricity and gas consumption (kgCO2eq) | |
COP | Coefficient of performance of the heat pump |
Daily coefficient of performance of the heat pump without auxiliaries | |
Daily coefficient of performance of the heat pump with auxiliaries | |
Heat pump electricity consumption without auxiliaries (kWhelec) | |
Heat pump electricity consumption with auxiliaries (kWhelec) | |
Hourly heat pump electricity consumption with auxiliaries (kWhelec) | |
Annual renewable energy from ASHP electricity consumption (kWhelec) | |
Gas or oil boiler consumption (kWhth) | |
DHW demand including storage and distribution losses (kWhth) | |
Heat pump production (kWhth) | |
HP production for DHW (kWhth) | |
HP production for SH (kWhth) | |
Heat pump production of the first machine (kWhth) | |
Heat pump production of the second machine (kWhth) | |
SH demand without storage losses (kWhth) | |
Heat extracted on the air source (kWhth) | |
Boiler heat production (kWhth) | |
Heat boiler production for DHW (kWhth) | |
Heat boiler production for SH (kWhth) | |
Overall seasonal performance of the heat pump and boiler | |
Annual seasonal performance factor of HP with auxiliaries | |
DHW distribution temperature at the storage outlet ( °C) | |
Temperature at condenser output ( °C) | |
DHW temperature at the heat exchanger inlet ( °C) | |
SH temperature before the mixing valve or before the tank ( °C) | |
SH distribution temperature after the mixing valve ( °C) | |
Outdoor temperature ( °C) | |
DHW temperature of the boiler before the tank ( °C) | |
SH temperature of the boiler before the tank ( °C) | |
CO2 content of Swiss electricity mix in hourly values (gCO2eq/kWhelec) | |
Emissions factor from gas or oil consumption (kgCO2/kWhth of gas) | |
Annual renewable share of total heat production (%) | |
Hourly Swiss electricity share produced from renewable sources (%) |
Appendix A. Control and Cascading of the HP Units and Gas Boiler (Hybrid System)
Appendix B. Carbon Emissions and Renewable Energy Fraction of the Swiss Electricity Mix
2017 | 2018 | 2019 | 2020 | Average | |
---|---|---|---|---|---|
Average annual Emissions (kgCO2eq/kWhelec) | 0.156 | 0.088 | 0.070 | 0.063 | 0.096 |
Average Swiss electricity share from renewable sources | 47.7% | 45.2% | 45.5% | 49.8% | 47.0% |
Appendix C. ASHP Production and Distribution Temperatures
Appendix D. Heat Production of Monovalent and Hybrid System
Appendix E. Comparison between the Actual Performance and Manufacturer
References
- OFEV. Inventaire des Gaz à Effet de Serre de la Suisse. Available online: https://www.bafu.admin.ch/ (accessed on 9 May 2022).
- OFEN. Bâtiments. Available online: https://www.bfe.admin.ch/bfe/fr/home/effizienz/gebaeude.html (accessed on 19 May 2022).
- Schneider, S.; Khoury, J.; Lachal, B.M.; Hollmuller, P. Geo-Dependent Heat Demand Model of the Swiss Building Stock: Method, Results and Example of Application; SCCER Future Energy Efficient Buildings & Districts: Geneva, Switzerland, 2018. [Google Scholar]
- Streicher, K.N.; Padey, P.; Parra, D.; Bürer, M.C.; Schneider, S.; Patel, M.K. Analysis of Space Heating Demand in the Swiss Residential Building Stock: Element-Based Bottom-Up Model of Archetype Buildings. Energy Build. 2019, 184, 300–322. [Google Scholar] [CrossRef]
- Quiquerez, L.; Lachal, B.M.; Monnard, M.; Faessler, J. Evaluation Quantitative de Scénarios de Développement du Marché de la Chaleur à Genève à l’Horizon 2035: Quel Rôle Pour les Réseaux de Chaleur? Services industriels de Genève: Geneva, Switzerland, 2016. [Google Scholar]
- Grandjean, B.; Schneider, S.; Hollmuller, P. Actual Energy Savings of More than 1000 Renovated Buildings in Geneva. J. Phys. Conf. Ser. 2021, 2042, 012145. [Google Scholar] [CrossRef]
- Khoury, J.; Hollmuller, P.; Lachal, B.M.; Schneider, S.; Lehmann, U. COMPARE RENOVE: Du Catalogue de Solutions à la Performance Réelle des Rénovations Energétiques (Ecarts de Performance, Bonnes Pratiques et Enseignements Tirés); Swiss Competence Center for Energy Research: Geneva, Switzerland, 2018. [Google Scholar]
- De Sousa Fraga, C. Heat Pump Systems for Multifamily Buildings: Which Resource for What Demand? University of Geneva: Geneva, Switzerland, 2017. [Google Scholar]
- RENOWAVE. Massive Decarbonization of the Swiss Building Stock. Research Proposal of the Innosuisse Flagship Initiative (Swiss Innovation Agency); RENOWAVE: Sittwe, Myanmar, 2021. [Google Scholar]
- Calame, N.; Cuvillier, G.; Rognon, F.; Montero Dominguez, O.; Brischoux, P.; Callegari, S.A.; Hollmuller, P.; Fraga, C.; Rüetschi, M. AirBiVal: Développement et Optimisation de Concepts Hybrides de Pompes à Chaleur Sur l’Air Pour des Immeubles Résidentiels Collectifs; University of Geneva: Geneva, Switzerland, 2021. [Google Scholar]
- CSD Ingénieurs SA Annex 50: HP in Multi-Family-Buildings Task 1: Market Overview, Country Report for Switzerland 2017; CSD: Fribourg, Switzerland, 2017.
- Calame, N. HPT—Heat Pumping Technologies—Heat Pump Retrofit Projects for Multi-Family Buildings—An Obstacle Run. SSRN 2021, 39, 4. [Google Scholar]
- Fabrice, R.; Alisa, Y.; Matthias, R. Retrofitting Fossil-Based Heating Systems with Air to Water Heat Pumps in Multifamily Houses. In Proceedings of the 12th IEA Heat Conference, Rotterdam, The Netherlands, 15–18 May 2017; p. 11. [Google Scholar]
- Calame, N.; Freyre, A.; Rognon, F.; Callegari, S.; Rüetschi, M. Air to Water Heat Pumps for Heating System Retrofit in Urban Areas: Understanding the Multi-Faceted Challenge. J. Phys. Conf. Ser. 2019, 1343, 012079. [Google Scholar] [CrossRef]
- Erb, M.; Peter, H.; Max, E. Feldanalyse von Wärmepumpenanlagen FAWA 1996–2003; FAWA: Zurich, Switzerland, 2004. [Google Scholar]
- Prinzing, P.; Matthias, B.; Stefan, B. Rapport "Mesures de Terrain des Installations de Pompes à Chaleur Saison de Chauffage 2020/2021"; Institut des Systèmes Energétiques (IESE), OST—Haute Ecole Spécialisée de Suisse Orientale: Delémont, Switzerland, 2022; p. 45. [Google Scholar]
- Huchtemann, K.; Müller, D. Evaluation of a Field Test with Retrofit Heat Pumps. Build. Environ. 2012, 53, 100–106. [Google Scholar] [CrossRef]
- Miara, M.; Christel, R.; Michael, P.; Danny, G. Feldmesung Warmenpumpen Gebäudebestand; Fraunhofer ISE: Freiburg im Breisgau, Germany, 2010; p. 21. [Google Scholar]
- Danny, G.; Jeannette, W.; Robert, L.; Sebastian, H.; Miara, M. Warmepumpen in Bestandsgebauden; Fraunhofer ISE: Freiburg im Breisgau, Germany, 2020; p. 200. [Google Scholar]
- Miara, M.; Danny, G.; Robert, L. Heat Pumps in Existing Residential Buildings. In Proceedings of the 13th IEA Heat Pump Conference, Jeju, Korea, 26–29 April 2021; p. 8. [Google Scholar]
- Xu, Z.; Zhao, W.; Shao, S.; Wang, Z.; Xu, W.; Li, H.; Wang, Y.; Wang, W.; Yang, Q.; Xu, C. Analysis on Key Influence Factors of Air Source Heat Pumps with Field Monitored Data in Beijing. Sustain. Energy Technol. Assess. 2021, 48, 101642. [Google Scholar] [CrossRef]
- Chesser, M.; Lyons, P.; O’Reilly, P.; Carroll, P. Air Source Heat Pump In-Situ Performance. Energy Build. 2021, 251, 111365. [Google Scholar] [CrossRef]
- IEA Heat Pump Technologies Annex 50: Heat Pumps in Multi-Family Buildings for Space Heating and DHW. Available online: https://heatpumpingtechnologies.org/annex50/ (accessed on 9 May 2022).
- Abid, M.; Hewitt, N.; Huang, M.-J.; Wilson, C.; Cotter, D. Domestic Retrofit Assessment of the Heat Pump System Considering the Impact of Heat Supply Temperature and Operating Mode of Control—A Case Study. Sustainability 2021, 13, 10857. [Google Scholar] [CrossRef]
- Asaee, S.R.; Ugursal, V.I.; Beausoleil-Morrison, I. Techno-Economic Feasibility Evaluation of Air to Water Heat Pump Retrofit in the Canadian Housing Stock. Appl. Therm. Eng. 2017, 111, 936–949. [Google Scholar] [CrossRef] [Green Version]
- Huchtemann, K.; Müller, D. Simulation Study on Supply Temperature Optimization in Domestic Heat Pump Systems. Build. Environ. 2013, 59, 327–335. [Google Scholar] [CrossRef]
- Le, K.X.; Huang, M.J.; Shah, N.N.; Wilson, C.; Artain, P.M.; Byrne, R.; Hewitt, N.J. Techno-Economic Assessment of Cascade Air-to-Water Heat Pump Retrofitted into Residential Buildings Using Experimentally Validated Simulations. Appl. Energy 2019, 250, 633–652. [Google Scholar] [CrossRef]
- Prud’homme, S.; Breton, S.; Tamasauskas, J.; Sager, J. A Simulation-Based Exploration of Air-Source Heat Pump Sizing in Canada; Natural Resources Canada: Ottawa, ON, Canada, 2020; p. 8. [Google Scholar]
- Bagarella, G.; Lazzarin, R.; Noro, M. Annual Simulation, Energy and Economic Analysis of Hybrid Heat Pump Systems for Residential Buildings. Appl. Therm. Eng. 2016, 99, 485–494. [Google Scholar] [CrossRef]
- Di Perna, C.; Magri, G.; Giuliani, G.; Serenelli, G. Experimental Assessment and Dynamic Analysis of a Hybrid Generator Composed of an Air Source Heat Pump Coupled with a Condensing Gas Boiler in a Residential Building. Appl. Therm. Eng. 2015, 76, 86–97. [Google Scholar] [CrossRef]
- Dongellini, M.; Naldi, C.; Morini, G.L. Influence of Sizing Strategy and Control Rules on the Energy Saving Potential of Heat Pump Hybrid Systems in a Residential Building. Energy Convers. Manag. 2021, 235, 114022. [Google Scholar] [CrossRef]
- Fitzpatrick, P.; D’Ettorre, F.; De Rosa, M.; Yadack, M.; Eicker, U.; Finn, D.P. Influence of Electricity Prices on Energy Flexibility of Integrated Hybrid Heat Pump and Thermal Storage Systems in a Residential Building. Energy Build. 2020, 223, 110142. [Google Scholar] [CrossRef]
- Klein, K.; Huchtemann, K.; Müller, D. Numerical Study on Hybrid Heat Pump Systems in Existing Buildings. Energy Build. 2014, 69, 193–201. [Google Scholar] [CrossRef]
- Li, G. Parallel Loop Configuration for Hybrid Heat Pump—Gas Fired Water Heater System with Smart Control Strategy. Appl. Therm. Eng. 2018, 138, 807–818. [Google Scholar] [CrossRef]
- Roccatello, E.; Prada, A.; Baggio, P.; Baratieri, M. Analysis of the Influence of Control Strategy and Heating Loads on the Performance of Hybrid Heat Pump Systems for Residential Buildings. Energies 2022, 15, 732. [Google Scholar] [CrossRef]
- Lämmle, M.; Bongs, C.; Wapler, J.; Günther, D.; Hess, S.; Kropp, M.; Herkel, S. Performance of Air and Ground Source Heat Pumps Retrofitted to Radiator Heating Systems and Measures to Reduce Space Heating Temperatures in Existing Buildings. Energy 2022, 242, 122952. [Google Scholar] [CrossRef]
- Fraga, C.; Hollmuller, P.; Schneider, S.; Lachal, B. Heat Pump Systems for Multifamily Buildings: Potential and Constraints of Several Heat Sources for Diverse Building Demands. Appl. Energy 2018, 225, 1033–1053. [Google Scholar] [CrossRef]
- Kelly, N.J.; Cockroft, J. Analysis of Retrofit Air Source Heat Pump Performance: Results from Detailed Simulations and Comparison to Field Trial Data. Energy Build. 2011, 43, 239–245. [Google Scholar] [CrossRef] [Green Version]
- Romano, E.; De Sousa Fraga, C.; Hollmuller, P. Réduction des émissions de CO2 pour pompes à chaleur en résidentiel collectif. In 26. Tagung des BFE-Forschungsprogramms "Wärmepumpen und Kälte"; Berner Fachhochschule: Burgdorf, Switzerland, 2020. [Google Scholar]
- OCEN. Energie—Degrés Jour. Available online: https://www.ge.ch/node/7569 (accessed on 15 May 2022).
- Khoury, J. Rénovation Energétique des Bâtiments Résidentiels Collectifs: État des Lieux, Retours d’Expérience et Potentiels du Parc Genevois; University of Geneva: Geneva, Switzerland, 2014. [Google Scholar]
- Quiquerez, L. Analyse Comparative des Consommations de Chaleur Pour la Production d’Eau Chaude Sanitaire Estimées à Partir De Relevés Mensuels: Etude sur un Echantillon de Bâtiments Résidentiels Collectifs Alimentés par un Réseau de Chaleur à Genève; Services industriels de Genève: Geneva, Switzerland, 2017. [Google Scholar]
- Romano, E.; Hollmuller, P.; Patel, M. Émissions Horaires de Gaz à Effet de Serre Liées à la Consommation Electricité—Une Approche Incrémentale pour Une Economie Ouverte: Le cas de la Suisse; Services industriels de Genève: Geneva, Switzerland, 2018. [Google Scholar]
- OFEV. Facteurs d’Émission de CO2 Selon l’Inventaire des Gaz à Effet de Serre de la Suisse. Available online: https://www.bafu.admin.ch/bafu/fr/home/themes/climat/etat/donnees/inventaire-gaz-effet-serre.html (accessed on 30 May 2022).
- SIA. Norme 385/2:2015—Installations d’Eau Chaude Sanitaire Dans les Bâtiments—Besoins en Eau Chaude, Exigences Globales et Dimensionnement; Société Suisse des Ingénieurs et des Architectes: Solothurn, Switzerland, 2015. [Google Scholar]
- Franco, A.; Bartoli, C.; Conti, P.; Testi, D. Optimal Operation of Low-Capacity Heat Pump Systems for Residential Buildings through Thermal Energy Storage. Sustainability 2021, 13, 7200. [Google Scholar] [CrossRef]
- Bagarella, G.; Lazzarin, R.; Noro, M. Sizing Strategy of on–off and Modulating Heat Pump Systems Based on Annual Energy Analysis. Int. J. Refrig. 2016, 65, 183–193. [Google Scholar] [CrossRef]
Monovalent | Hybrid | |
---|---|---|
Type of building | Residential | Mixed (residential + commercial) |
Construction year | 1972 | 1992 |
Heated floor area | 4047 m2 | 7563 m2 |
Old heating system | Oil boiler (319 kWth) | Gas boilers (2 × 200 kWth) |
New heating system 1 | 2 industrial ASHPs (2 × 156 kWth) | 6 ASHPs (6 × 34 kWth) + Existing gas boiler (200 kWth) |
SH demand (measured) | 58 kWhth/m2/yr | 64 kWhth/m2/yr |
SH demand (normalized) 2 | 77 kWhth/m2/yr | 72 kWhth/m2/yr |
DHW demand 3 | 55 kWhth/m2/yr | 30 kWhth/m2/yr |
Monitoring period | July 2018–June 2020 | July 2017–June 2019 |
Monovalent | Hybrid | |
---|---|---|
2.29 | 2.28 | |
2.29 | 1.28 | |
HP fraction | 100% | 67% |
Renewble energy fraction | 75% | 43% |
Emissions before ASHP renovation | 42 kgCO2eq/m2/yr | 40 kgCO2eq/m2/yr |
Emissions after ASHP renovation | 3.4 kgCO2eq/m2/yr | 13.1 kgCO2eq/m2/yr |
Emissions savings | 92% | 68% |
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Montero, O.; Brischoux, P.; Callegari, S.; Fraga, C.; Rüetschi, M.; Vionnet, E.; Calame, N.; Rognon, F.; Patel, M.; Hollmuller, P. Large Air-to-Water Heat Pumps for Fuel-Boiler Substitution in Non-Retrofitted Multi-Family Buildings—Energy Performance, CO2 Savings, and Lessons Learned in Actual Conditions of Use. Energies 2022, 15, 5033. https://doi.org/10.3390/en15145033
Montero O, Brischoux P, Callegari S, Fraga C, Rüetschi M, Vionnet E, Calame N, Rognon F, Patel M, Hollmuller P. Large Air-to-Water Heat Pumps for Fuel-Boiler Substitution in Non-Retrofitted Multi-Family Buildings—Energy Performance, CO2 Savings, and Lessons Learned in Actual Conditions of Use. Energies. 2022; 15(14):5033. https://doi.org/10.3390/en15145033
Chicago/Turabian StyleMontero, Omar, Pauline Brischoux, Simon Callegari, Carolina Fraga, Matthias Rüetschi, Edouard Vionnet, Nicole Calame, Fabrice Rognon, Martin Patel, and Pierre Hollmuller. 2022. "Large Air-to-Water Heat Pumps for Fuel-Boiler Substitution in Non-Retrofitted Multi-Family Buildings—Energy Performance, CO2 Savings, and Lessons Learned in Actual Conditions of Use" Energies 15, no. 14: 5033. https://doi.org/10.3390/en15145033