Space Heating Demand Research Articles

Identifying the influence of user behaviour on building energy consumption based on model-based analysis of in-situ monitoring data

This study carries out a comprehensive comparison between design and monitoring results in a building located in Innsbruck, Austria, with the focus on the user influence as an important part of a fault detection strategy. The space heating consumption shows a difference from the design (of 11 kWh/(m2a)), with an excess of 22 kWh/(m2a) in 2019 and 28 kWh/(m2a) in 2020. Contrarily, monitored energy consumption for domestic hot water and appliances are lower than the design. Electricity consumption for mechanical ventilation and photovoltaic production are similar to the design. A fault detection and diagnosis analysis is carried out at building and room level (apartments and common rooms), studying the correlation between the energy consumption and temperature of the corresponding space. Several methods are tested to identify the rooms with non-standard behaviour with respect to window ventilation, setpoint temperature and a combination of them and their influence on the space heating demand. The analysis assesses an influence of the occupants behaviour (in terms of higher window ventilation and setpoint temperature) of 20–32% on the space heating demand, which does not entirely justify the high mismatch between measured and design values. Combinations of known, likely and possible causes for the higher monitored space heating are investigated and show the upper and lower bound of user behaviour and building deficiencies.

Decarbonizing residential energy consumption under the Italian collective self-consumption regulation

The recent Italian regulatory framework is promoting Collective Self-Consumption to play a key role in the energy transition. In fact, this new scheme allows sharing and exchange of electricity produced from Renewable Energy Sources (RES) among different end-users living in the same multi-family building block. In this context, this paper aims to perform an energy, economic and environmental assessment of creating a RES-based energy community formed by end-users located in the same residential building, taking into account the currently available incentive schemes. In particular, two different progressive scenarios have been analysed: the first one includes only a photovoltaic system to supply the aggregated electricity demand of the apartments, while a heat pump is further integrated in the second scenario for supplying and electrifying/decarbonizing also the space heating demand of the building. Available temperature and solar irradiance datasets at national level were then used to spread the analysis to the whole country, at different latitudes. Although differences exist at regional levels for the proposed scenarios, the results highlight how the RES-based Collective Self-Consumption scheme is economically profitable for Italian residential end-users with cost savings up to 32% and environmentally sustainable with carbon emissions reduction up to 60%. • Economic, energy and environmental analysis of PV and HP for Italian households. • Energy modeling considering solar radiation and air temperature variability with GIS. • The results highlight how the economic and environmental perspectives are positive. • The new regulatory framework concerning energy sharing improve RES diffusion.

Role of temporary thermostat adjustments as a fast, low-cost measure in reducing energy imports

Efforts to combat climate change involve long-term plans to reduce the energy demand and increase the share of locally generated renewable energy. However, a sudden change in the geopolitical situation may require an even more rapid response to reduce energy imports through energy-efficiency improvements. In the building sector, retrofits to the building envelope and heating systems are effective, yet time- and cost-intensive to improve energy efficiency. A fast, low-cost measure to address this need is to lower the temperature set-points in building heating systems to within comfortable limits. Here, we show the impact of reducing the temperature set-point by 1 °C on heating demand at different scales—building, regional, and national—using demand simulation of 240 Swiss building archetypes and clustering-based upscaling methods. We demonstrate a nearly 6% reduction in the residential space heating demand at the national level, about a third of which is met with natural gas. More importantly, the presented approach highlights potential implications of the proposed measure across a national residential building stock, considering differences in climate and building archetypes, as well as their spatial distribution.

Economic and Environmental Analysis of Incorporating Geothermal District Heating System Combined with Radiant Floor Heating for Building Heat Supply in Sarein, Iran Using Building Information Modeling (BIM)

Despite the considerable breakthrough in district heating systems (DHS) globally, there is not yet any policy on developing this technology in Iran. This country has a high range of energy demand, while renewable energies play a minor role in its energy supply chain. Furthermore, the world is going through a transition towards renewable resources, which currently consist of only 10% of the total energy mix. As the first contribution in this area, this paper aims to design a 100% renewable DHS integrated with radiant floor heating for a group of residential buildings in Sarein, Iran. Moreover, the literature proposes a novel approach for combining geothermal energy and Municipal Solid Waste (MSW) to achieve a 100% renewable energy system. Building Information Modeling (BIM) is used for thermal analysis by 3D designing the buildings in SketchUp and OpenStudio and simulating the heat load in EnergyPlus. Three scenarios are presented to better compare the DHS with the decentralized heating system regarding fuel consumption, as well as environmental and economic aspects. The town’s existing heating system that consumes natural gas for both space heating and hot water demand is referred to as the IHS-G scenario. The DHS-G scenario represents an 87% renewable DHS system, working with natural gas and geothermal energy, while the DHS-MSW scenario is a 100% renewable system, consuming both geothermal energy and Municipal Solid Waste (MSW). Finally, findings suggest that DHS-MSW and DHS-G scenarios reduce the annual energy consumption of buildings by about 595 and 33 toes, respectively. Hence, the greenhouse gas effect will alleviate by mitigating the emission of 1403 and 1339 tons of CO2-eq./year, respectively. Moreover, exporting the extra natural gas through both LNG and pipeline provides about 26 million and 28 million USD/year revenue in DHS-G and DHS-MSW scenarios.

Residential Building Construction Techniques and the Potential for Energy Efficiency in Central Asia: Example from High-Altitude Rural Settlement in Kyrgyzstan

Building construction in rural Kyrgyzstan is heavily dominated by earthen buildings. Old and inappropriate residential building structures contribute significantly to high domestic space heating energy consumption. Therefore, it is necessary to understand the relevant building construction techniques. However, the scant information on Kyrgyz building techniques, especially for high-altitude rural settlements, was the prime motivation to perform the presented study. The key objective of the study is to investigate residential building construction techniques in high-altitude rural Kyrgyzstan, and this was to be achieved by house visits during field trips, literature review, and pilot interviews with local people. The analysis enabled the detailed identification of individual building envelopes as well as predominant building materials to be recorded. Based on the assessment, a housing profile was created that represents the typical characteristics of traditional rural Kyrgyz houses. Furthermore, the study demonstrates the potential for energy savings in rural Kyrgyz houses of 50–70%. However, local conditions prevent people from making improvements to all domestic energy efficiency parameters simultaneously. Therefore, the study developed a ‘sequential roadmap’ to reduce domestic space heating demand in different phases based on simulation studies. Existing low-income rural Kyrgyz habitations can use the presented roadmap to reduce domestic space heating demand sequentially to overcome financial barriers and, therefore, contribute to establishing sustainable buildings in Kyrgyzstan. These results may be partially replicated in other Central Asian rural communities depending on their location and building characteristics.

Space heating demand profiles of districts considering temporal dispersion of thermostat settings in individual buildings

Future energy infrastructures are expected to be smart, with the application of energy storage and demand-side management strategies. To size the energy storage and assess the flexibility of the heat demand in a district, insight into its heat demand profile is a prerequisite.A tool was developed to generate the hourly space heating demand of a district. A crucial element in the calculation is the behaviour of occupants, particularly the temporal dispersion of thermostat settings in individual buildings. This dispersion smooths out the morning (and evening) peaks in the space heating demand of a district when occupants turn up their thermostats.Hourly gas consumption data were obtained of 8077 buildings with gas fired boilers in 2020. A dynamic resistance capacitance (RC) building model of a single aggregated building representing the 8077 dwellings was used to calculate their space heating demand profile in 2020. A comparison with the actual gas consumption data (corrected for domestic hot water use and cooking) allowed the estimation of the temporal thermostat settings, the dispersion thereof and the thermostat temperature levels of buildings in the district. The combined space heating demand profile of the individual buildings calculated using the same RC building model (each with its own thermostat settings) reproduced the actual space heating demand profile relatively well.

DEVELOPMENT AND TESTING OF THE CITYJSON ENERGY EXTENSION FOR SPACE HEATING DEMAND CALCULATION

Abstract. 3D city models are frequently used to acquire and store energy-related information of buildings for energy applications. In this context, CityGML is the most common data model, and the Energy ADE, one of its most complex extensions, provides a systematic way of storing detailed energy-related data in XML format. Contrarily, even though CityGML’s JSON-based encoding, CityJSON, has an extension mechanism, an energy-related CityJSON Extension is missing. This paper, therefore, presents the first results of the development of a CityJSON Energy Extension and space heating demand calculation is utilized as the use case. The simplified version of the Energy ADE, called the Energy ADE KIT profile, is used to create a semi-direct translation to the CityJSON Energy Extension. This Extension is then validated through the official validator of CityJSON and the use case, and improvements are made considering the validation results. The space heating demand is calculated according to the Dutch standard NTA 8800 for a subset of Rijssen-Holten in the Netherlands although the solar gains calculation requires further review. The results show that the final CityJSON Energy Extension provides full support for space heating demand calculations based on the NTA 8800 and eliminates the deep hierarchical structure of the Energy ADE. A comparison on CityJSON file sizes shows a 25.2 MB increase after the required input data is stored in a CityJSON + Energy Extension file, which is not significant considering the high amount of data stored in the file. Overall, this paper shows that the CityJSON Energy Extension could provide an easy-to-use alternative to the CityGML Energy ADE.

A methodology to estimate space heating and domestic hot water energy demand profile in residential buildings from low-resolution heat meter data

This article presents a new methodology to disaggregate the energy demand for space heating (SH) and domestic hot water (DHW) production from single hourly smart heat meters installed in Denmark. The new approach is idealized to be easily applied to several building typologies without the necessity of in-depth knowledge regarding the dwellings and their occupants. This paper introduces, tests, and compares several algorithms to separate and estimate the SH and DHW demand. To validate the presented methodology, a dataset of 28 Danish apartments with detailed energy monitoring (separated SH and DHW usage) is used. The comparison shows that the best method to identify energy demand data points corresponding to DHW production events is the so-called “maximum peaks” approach. Furthermore, the best algorithm to estimate the SH and DHW separately is a combination of two methods: the Kalman filter and the Support Vector Regression (SVR). This new methodology outperforms the current Danish compliances typically used to estimate the annual DHW usage in residential buildings.

Requirements for renovating residential buildings in the Netherlands towards lower temperature supply from district heating.

In the Netherlands, district heating with a lower temperature supply (<70°C) will play a crucial part in accomplishing the energy transition goals of delivering natural gas-free sustainable heating to dwellings. The existing dwellings often require energy renovations to make them suitable for lower temperature heating. However, choosing renovation strategies that promote the transition to lower temperature district heating while improving energy efficiency and thermal comfort is challenging. This study aims to identify minimum renovation requirements for comfortably heating homes using lower temperature heat from district heating. Identifying minimum renovation strategies to prepare existing dwellings for lower temperature district heating would be vital in addressing the European Renovation Wave’s target of improving worst-performing buildings. For the same, the study uses a typical intermediate terraced house built before 1945 as a case study to investigate renovation strategies based on four levels of renovation intervention (no renovation, basic, moderate and deep). The impact of renovations on space heating demand and thermal comfort was tested with medium (70/50°C) and low supply (55/35°C) temperatures against key performance indicators (KPIs) using dynamic simulation. The study found that for the case study dwelling, moderate renovation strategy of upgrading the building envelope insulation by 0.40 W/m2K for opaque parts and 1.5 W/m2K for glazing, improving the airtightness by 0.3h-1 and replacing existing radiators with LT radiators can be considered as a no-regret solution for comfortably heating homes with both medium and lower temperature supply from district heating.

Generating heat demand profiles of neighbourhoods

To size future energy infrastructures, that may include energy storage or demand side management, insight in heat demand profiles of neighbourhoods is a prerequisite. TNO developed a tool to generate heat demand profiles. Using public sources, the tool makes an inventory of buildings in the neighbourhood. For each building, a building archetype that most closely resembles it is selected, and its space heating demand profile is simulated using a dynamic resistance capacitance (RC) building model. To this, a repetitive daily profile for domestic hot water (DHW) preparation and cooking is added. The heat demand profile of the neighbourhood is calculated by summing the profiles of buildings in it, taking a dispersion of thermostat times into account. The current version of the tool, which is still under development, was validated by comparing the annual gas consumption of a number of neighbourhoods with actual data. While the tool predicted annual gas consumption of pre-1960 neighbourhoods reasonably well, for more recent neighbourhoods, the tool underestimated the annual gas consumption by typically 30%.

The economic potential of district heating under climate neutrality: The case of Austria

This paper focuses on the requirement of the Energy Efficiency Directive for assessing the potential of efficient heating and cooling. The paper describes the method for calculating the economic potential of efficient district heating (DH) in Austria under different scenarios, assuming the full decarbonisation of the heating sector by 2050. A spatially explicit approach is used to derive heat demand density maps, heat distribution costs and potential DH areas. The obtained areas are clustered, and depending on their potential spreads, up to four supply portfolios on the installed generation capacities are assessed in each cluster. While this method maintains the level of detail, it significantly reduces the number of required sensitivity analyses. Finally, the least cost portfolios of DH supply in each cluster are identified and compared with the costs of individual heat supply. The economic potential of DH by 2050 is calculated accordingly. The analyses revealed that the DH market share within DH areas is the main driver of DH competitiveness. Depending on the scenario, the economic DH potential varies between 13% and 50% of space and water heating demand in Austria. The extensive application of renewable gases in this sector was not economically feasible under any scenario.

Solar-Driven Sorption System for Seasonal Heat Storage under Optimal Control: Study for Different Climatic Zones

Solar thermal energy coupled to a seasonal sorption storage system stands as an alternative to fossil fuels to supply residential thermal energy demand in climates where solar energy availability is high in summer and low in winter, matching with a high space heating demand. Sorption storage systems usually have a high dependency on weather conditions (ambient temperature and solar irradiation). Therefore, in this study, the technical performance of a solar-driven seasonal sorption storage system, using an innovative composite sorbent and water as working fluid, was studied under three European climates, represented by: Paris, Munich, and Stockholm. All scenarios analyses were simulation-based under optimal system control, which allowed to maximize the system competitiveness by minimizing the system operational costs. The optimal scenarios profit from just 91, 82 and 76% of the total sorption system capacity, for Paris, Munich, and Stockholm, respectively. That means that an optimal control can identify the optimal sorption storage size for each location and avoid oversizing in future systems, which furthermore involves higher investment costs. The best coefficient of performance was obtained for Stockholm (0.31), despite having the coldest climate. The sorption system was able to work at minimum temperatures of −15 °C, showing independence from ambient temperature during its discharge. In conclusion, a seasonal sorption system based on selective water materials is suitable to be integrated into a single-family house in climates of central and northern Europe as long as an optimal control based on weather conditions, thermal demand, and system state is considered.

Space temperature policy towards net-zero: recommendations from a systematic review of UK HEI heating policies

ABSTRACT The UK government has committed to reducing its carbon emissions to net-zero by 2050. Higher education institutions (HEIs) are high energy users, with the largest proportion of their energy demand for space heating; an area still dominated by carbon-intensive fuels. This research addresses the UK HEI space temperature policy landscape, making direct links between space temperature policy and carbon management, advocating the development of evidence-based policies as a critical tool for reducing carbon emissions within the sector. Sixty-six space temperature policies were reviewed, and five experienced energy managers were interviewed to understand the range, development and use of space temperature policies in UK HEIs. The research identified a lack of consistency across these policies, leading to missed opportunities for making energy and carbon savings. The research highlights gaps in the available data and literature needed to connect policy to its effectiveness, and identifies the use of policy as a defensive tool against complaints rather than an active driver of energy reduction. A series of recommendations are proposed for national and institutional policymakers, suggesting areas for improvement and future research to facilitate effective development and practice in space temperature policy towards net-zero.

Creating Comparability among European Neighbourhoods to Enable the Transition of District Energy Infrastructures towards Positive Energy Districts

Planning the required energy infrastructure for the energy transition is a crucial task for various neighbourhood concepts, such as positive energy districts. However, energy planning often comes with the challenges of data shortages and a lack of comparability among solutions for different districts. This work aims to enable this comparability by introducing an approach for categorising districts according to parameters that are relevant for the planning of neighbourhood energy infrastructures. Four parameters (climate, floor space index, heating demand and share of residential buildings) and their respective ranges (bands) were derived from the literature. Additionally, this work visualised the combination of all parameter bands across Europe to conveniently showcase districts that are comparable according to the selected parameters. This approach and its visualisation could be used in urban planning to share knowledge from existing energy district projects with those planned in comparable districts.

Multi-mode operation and thermo-economic analyses of combined cooling and power systems for recovering waste heat from data centers

Current solutions for waste heat recovery from data centers are mainly district heating and refrigeration. However, intermittent demand for space heating and cooling resulted from seasonal or spatial variations makes inefficient utilization of waste heat. To better harvest the low-grade thermal energy in data centers, combined cooling and power systems are proposed, with the capability of adjusting the energy output to meet diverse energy demands hourly and seasonally. In total, six cogeneration systems with different configurations are investigated, with the power cycles being either organic Rankine cycle or Kalina cycle, and the refrigeration cycles being vapor compression refrigeration cycle, ejector expansion refrigeration cycle or absorption refrigeration cycle. Depending on the energy demands of data centers, each system has three operation modes: combined cooling and power, power alone and cooling alone. The performance is evaluated in terms of both the thermodynamic and economic performance by parametric study and multi-objective optimization. Results show that the organic Rankine cycle/absorption refrigeration cycle hybrid system has the best thermal-economic performance in all three modes. According to the comprehensive evaluation of the TOPSIS method and the entropy weight method, the energy efficiency at the optima is 58.13%, and the unit cost of product is 4.25 $/GJ, with the net power output of 4.25 kW and the cooling capacity of 150 kW.

Determinants of energy demand for residential space heating in Turkey

A significant portion of household energy requirements is used for space heating. Although the fundamental factors determining household energy consumption have been the focus of many studies, they have neglected to consider the effect of unobserved heterogeneity, which has the potential to play a significant role as a determining factor in energy consumption. The study analyzes household decisions in choosing an energy source for residential space heating applying a random effect ordered logit model on Income and Living Conditions Longitudinal Micro Data Set for the years 2016–2019 to fulfill this gap in the literature. The results indicate that selection of residential space heating type (dried animal dung, charcoal, wood, natural gas, electricity) is influenced by socioeconomic and dwelling factors. We also found that the energy ladder hypothesis is valid for households in Turkey.

The spatial and temporal mismatch phenomenon in solar space heating applications: status and solutions

Building space heating has led to tremendous energy consumption globally. The mismatch between fluctuating solar energy resources and stochastic space heating load shall be solved to realize the transition from fossil energy to solar energy for space heating. In the spatial aspect, the discrepancy of solar energy resources in different regions is considerable and the heating load is also varying with the climate type, population density, and so on. In the temporal aspect, the seasonal and diurnal solar energy resource usually has an opposite trend to the actual space heating demand. The spatial and temporal mismatch between solar energy and heating load cause inefficient solar energy utilization and prejudice the decarbonization goal. This work is focused on the status and solutions to this phenomenon, and the state-of-art from the perspective of both the supplement and demand sides are reviewed, as well as the extensive policy outlook for mitigating the mismatch problem in solar space heating applications. Finally, the future investigation suggestions and research gaps on this scientific problem are concluded from this work.

Optimization of supercooling, thermal conductivity, photothermal conversion, and phase change temperature of sodium acetate trihydrate for thermal energy storage applications

The demand for space heating and domestic hot water has caused an increase in building-energy consumption. Thermal energy storage systems can effectively solve the mismatch between heat supply and demand. Phase change materials (PCMs) can be served as the thermal storage media for thermal energy storage systems. In this study, the tailor-made sodium acetate trihydrate (SAT, a kind of PCM) was developed. Multi-wall carbon nanotubes (MWCNTs) was employed as the nucleation agent of SAT, meanwhile other carbon-based materials, including carbon fiber (CF), expanded graphite (EG), and graphene nanoplates (GNPs), were synergistically used as thermal conductivity and photothermal conversion enhancers. Ammonium chloride (NH4Cl) was innovatively adopted as a phase change temperature regulator for SAT. The results showed that the supercooling degree of SAT decreased to 0.9 °C with the presence of MWCNTs. The thermal conductivity of SAT improved by 54.9%, and the photothermal conversion efficiency increased to 89.3% after incorporating GNPs into the SAT/MWCNTs composite. Furthermore, phase change temperature of the SAT/MWCNTs composite, ranged from 57.5 °C to 45.1 °C, could be prepared by adjusting NH4Cl contents for satisfying different application scenarios. The results indicate that the prepared SAT composites can be potentially used in different thermal energy storage systems.

Robustness of district heating versus electricity-driven energy system at district level: A multi-objective optimization study

This article compares the robustness of the optimal choice of technologies for two Smart Energy Systems architectures at district level, illustrated by a case study representative of a newly built district in Grenoble, France. The electricity-driven architecture relies on the national electric grid, decentralized photovoltaic panels and decentralized heat pumps for heat production building by building. The alternative architecture consists of a district heating network with multiple sources and equipment for centralized production of heat. Those are a gas boiler plant, a biomass-driven cogeneration plant, a solar thermal collector field, and a geothermal heat pumping plant (grid-driven or photovoltaics-driven). Electric and heat storages are considered in both architectures. The sizing and operation of both architectures are optimized via linear programming, through a multi-objective approach (total project cost versus carbon dioxide emissions). Both architectures are compared at nominal scenario and at sensitivity scenarios. It is concluded that the electricity-driven architecture is less robust, especially to uncertainties in space heating demands (+150%/−30% impact on costs) and in heat pump performance (+35%/−15% in costs). Meanwhile, the multi-source architecture is less sensitive to space heating demands (+110%/−30%) and has negligible sensitivity to the rest of parameters except photovoltaic panels efficiency (+14%/−7%).

Resilience optimization of multi-modal energy supply systems: Case study in German metal industry

The energy-intensive industry sector, including the metal industry, strongly depends on resilient energy supply concepts. Environmental concerns, e.g. about the future availability of groundwater for cooling, force companies to analyze the resilience of their energy supply systems. The use of heat pumps, electrolysers and combined heat-and-power units couples multi-modal supply systems for electricity, thermal demands, and process gases. This paper presents an integrated design approach for industrial supply systems showcased for a real-world case of a German copper mill. System resilience is evaluated for both environmental risk mitigation and technical robustness. Quantitative results reveal heat pumps as an attractive technology option: Groundwater withdrawal for cooling is cost-efficiently reduced by 18%, whereas the waste heat can be utilized to meet more than 70% of the space heating demand. This enhances system resilience to a future tightening of the regulatory environment for water withdrawal and increasing carbon prices. The mill experiences only rarely grid outages due to the high reliability of the German power system. Additional distributed generators or storages with the ability of islanding therefore do not appear economically beneficial in this case study.