Tertiary Sector Buildings Research Articles

Adoption of Innovative Energy Facilities in the Tertiary Sector Buildings: Exploring Interdependencies and Key Drivers

Innovative energy facilities, such as solar panels, heat pumps, and smart control ventilation, offer substantial opportunities to improve energy efficiency and environmental performance in the tertiary sector, aligning with green building objectives. This study aims to identify the key factors influencing the adoption of these facilities by small and medium-sized enterprise owners in the tertiary sector and to explore the interdependencies among them. To achieve this, we employed a stated choice experiment to assess preferences and decision-making by presenting respondents with multiple hypothetical scenarios, each containing alternatives described by varying attributes. A simultaneous equation model was used to analyze the key drivers of adoption and the interrelationships among these facilities. The results reveal that cost-related attributes and government incentives significantly impact the acceptance of energy facilities. Notably, while environmental responsibility is slightly associated with solar panel adoption, it shows no significant link with heat pumps or ventilation systems. Furthermore, we identified a bi-directional relationship between the adoption of solar panels and heat pumps, suggesting that acceptance of one positively influences the other. Conversely, a unidirectional relationship exists between ventilation and solar panels, where the adoption of ventilation positively influences solar panel adoption, but not the other way around. These findings contribute to a deeper understanding of decision-making processes in green building projects and provide valuable insights for policymakers and industry stakeholders aiming to promote sustainable energy solutions in the tertiary sector.

Cost-Optimality Assessment of a Solar Trigeneration System for Tertiary Sector Buildings in Greece

To pave the way towards buildings’ decarbonization in the context of the European Union’s (EU) policy, the methodology of cost-optimality assessment based on regulation 244/2012/EU is a useful tool to explore and foster the application of energy technologies in buildings. Meanwhile, the fostering of concentrated solar power is included in the EU solar energy strategy. In this study, the cost-optimal methodology is employed for the techno-economic assessment of the integration of a novel solar, multi-purpose energy technology, namely a parabolic trough collector-based trigeneration system, in two building types with different characteristics, namely an office and a hospital, in Greece, thus allowing the evaluation of the cost-optimal system design and the impact of the building type on the system’s techno-economic performance. Reference buildings are defined and their energy demand is calculated through dynamic energy simulations. The trigeneration system’s performance for different design scenarios is then parametrically investigated using a simulation model. For each scenario, energy, environmental and economic indicators are calculated and the cost-optimal designs are extracted. In the cost-optimal implementation, the system covered 18.19–36.39% and 3.58–15.71% of the heating and cooling demand, respectively, while the reduction of the primary energy consumption and emissions was estimated at 10–14% and 10–16%, respectively. However, differences between the buildings related to the operation schedule and the loads led to the implementation of the system being economically more attractive in the hospital, while for the office, financial support is necessary for a viable investment.

Experimental test of a building thermal system for preventive maintenance based on thermoeconomic analysis

An analysis of the sectorial structure of energy consumption shows that residential and tertiary sector buildings are the third-highest consumers, responsible for 29.5% of a city’s final energy consumption. The Building Quality Control Laboratory of the Basque Government aims to promote quality, innovation, and sustainability in buildings. To accomplish this goal, it has constructed an experimental facility with different energy generation technologies and a very versatile control system for testing different energy systems and operation modes. In this study, we tested a facility for supplying domestic hot water and heating for a multi-family house by means of a condensing boiler and an aerothermal heat pump (together with the corresponding control). This installation could reproduce the thermal demands required to be satisfied by the generation equipment through a programmed operation of the installation based on real demands. Additionally, this installation was analyzed using thermoeconomics (TE) to solve problems unable to be solved using traditional energy analyses based on the First Law of Thermodynamics. These problems include: (1) Determining the costs of the products of the installation based on physical criteria, (2) detecting the places where losses actually occur, evaluating their costs, and proposing cost-effective improvements, and (3) diagnosing issues in the installation. As a result, this paper suggests a solution to the preventive maintenance problems confronting the technical maintenance personnel for thermal installations in buildings by applying TE knowledge and using real data collected from sensors.

Techno-Economic Analysis of a Hydrogen-Based Power Supply Backup System for Tertiary Sector Buildings: A Case Study in Greece

In view of the European Union’s strategy on hydrogen for decarbonization and buildings’ decarbonization targets, the use of hydrogen in buildings is expected in the future. Backup power in buildings is usually provided with diesel generators (DGs). In this study, the use of a hydrogen fuel cell (HFC) power supply backup system is studied. Its operation is compared to a DG and a techno-economic analysis of the latter’s replacement with an HFC is conducted by calculating relevant key performance indicators (KPIs). The developed approach is presented in a case study on a school building in Greece. Based on the school’s electricity loads, which are calculated with a dynamic energy simulation and power shortages scenarios, the backup system’s characteristics are defined, and the relevant KPIs are calculated. It was found that the HFC system can reduce the annual CO2 emissions by up to 400 kg and has a lower annual operation cost than a DG. However, due to its high investment cost, its levelized cost of electricity is higher, and the replacement of an existing DG is unviable in the current market situation. The techno-economic study reveals that subsidies of around 58–89% are required to foster the deployment of HFC backup systems in buildings.

A Comparison of Direct and Indirect Flexibilities on the Self-Consumption of an Office Building: The Case of Predis-MHI, a Smart Office Building

The purpose of this paper is to provide a method for assessing the impact of direct and indirect flexibilities on the self-consumption of office buildings. The goal is to assess how both the human actors and technical interventions can affect or mitigate deviations in the self-consumption level of a building from its optimal. This paper considers the Predis-MHi platform (a living lab) as a representative case study and applies a Mixed Integer Linear Programming optimization to manage both the direct (stationary battery charging) and indirect flexibilities (Electric Vehicle charging when users plug and unplug their vehicles). Our results indicate that the potential for a building’s self-consumption improvement using indirect flexibilities does exist and can be quantified. However, this type of flexibility is highly dependent on human actors which presents a high level of uncertainty and is difficult to account for in all stages of a building’s development and use. Direct flexibilities such as stationary battery storage can be used to mitigate the undesired effects of having significant levels of indirect flexibilities on a tertiary sector building’s energy performance. The results from this study could potentially be modeled into an indicator, which would serve to influence occupant behavior towards a desired optimal.

Bidding strategies for excess heat producers participating in a local wholesale heat market

The heating sector of the European Union covers 80% of the household’s final energy consumption, which shows its relevance for the energy transition to the carbon neutral society, as set out in the Green Deal. Since most of the heat demand is located in the high heat density areas, district heating shows to be a promising solution for reducing the environmental impact of this sector, as it enables the utilisation of renewable energy sources and the use of high efficiency production technologies. An especially interesting source for district heating is excess heat from various industries and tertiary sector buildings, which has a significant technical potential. However, to enable excess heat producers to supply their heat to district heating, third-party access needs to be granted, which calls for a deregulated heat market.This work consists of analysing two different bidding strategies which can be applied on the heat market: total cost and marginal cost biding. The focus here is to research the feasibility of the excess heat sources when different bidding strategies are used, especially when low temperature excess heat is considered, which has variable hourly costs due to the electricity demand for operating a heat pump. The results show that, despite the increased capacity factor of low temperature excess heat when marginal cost biding is used, it remains infeasible when supplying heat to the high temperature district heating networks through a heat market. Therefore, lower temperature district heating is a necessity for a feasible utilisation of low temperature excess heat. Finally, the effect of the power market prices on the low temperature excess heat feasibility was analysed and it was shown that it is significant, which led to the conclusion that introducing a higher share of renewables into the power market could foster the utilisation of these heat sources.

Simulation and optimal control of heating and cooling systems: A case study of a commercial building

This paper proposes a novel energy conservation measure that optimizes the planning of heating and cooling systems for tertiary sector buildings. It consists of a model-based predictive control approach that employs a grey-box model built from the building and weather data that predicts the building heat load and indoor temperature. Different from classical optimization approaches where the discretized differential algebraic equations are integrated into the optimization formulation, our model is calibrated using black-box multiobjective optimization, which allows for decoupling the predictive model from the optimization problem, thus having more flexibility and reducing the total computational time. Moreover, rather than requiring the angle of solar radiation, solar orientation and solar masks to calculate the radiation data, our approach requires only a simple model of the solar irradiance. The calibrated model is then used by heating and cooling optimization strategies that aim at reducing the energy consumption of the building in the next day while satisfying the indoor thermal constraints. The proposed approach was applied in a case study of a commercial building during heating and cooling seasons and the results show that it was able to yield up to 12% of energy savings while having a mean power forecast error of 8%.

Performance Assessment of Solar Cooling Systems with Energy Storage

The paper presents a complete solar cooling comparison. A detailed model of a tertiary sector building has been evaluated in three locations (Riyadh, Abu Dhabi, and Palermo) and coupled with four solar cooling systems: two solar thermal cooling systems (Li-Br absorption chiller and adsorption chiller), a solar Desiccant Evaporative Cooling system and a solar electric cooling (Photovoltaic coupled with Compression chiller). A multi-variable optimization procedure selects the optimal size of each component. The results show that the solar cooling system based on absorption chiller satisfied the cooling demand regardless of the site location whilst the performance of the Desiccant Evaporative Cooling system is dramatically affected by ambient conditions. The electric solar cooling option shows the best overall efficiency and appears a costeffective solution despite the high cost of the storage system.

Tackling thermal integration in the synthesis of polygeneration systems for buildings

A novel methodology is proposed for the synthesis of polygeneration systems in tertiary sector buildings with detailed thermal integration. The methodology involves a systematic approach that combines Pinch Analysis, mathematical programming, and the definition of a superstructure with thermal flexibility whereby mass flows can exchange heat in various temperature intervals. With the detailed characterization of the thermal energy flows associated with the thermal energy technologies and services to be supplied to the building, the optimization procedure provides a more realistic system configuration, ensures that thermodynamic principles are satisfied, and allows for synergies and potential benefits to emerge. The methodology is first introduced through a simple example of a gas engine-based energy system, highlighting the necessity of a detailed characterization of the hot and cold flows regarding their quantity and quality levels. Then, the approach is applied to the case study of a Brazilian university hospital that requires electricity, steam, hot water, and chilled water. The optimization is formulated as a multi-period mixed integer linear programming model that minimizes the total annual cost of installing and operating the system using local-based data. The results show the technical and economic interest of deploying cogeneration gas engines to cover electricity and thermal energy services. Besides, a strong synergy is observed between the cogeneration gas engine and the single-effect absorption chiller. Thus, it is demonstrated how a preliminary analysis of thermal integration opportunities must be an integral part of the optimal synthesis of energy supply systems.

Seasonal heat performances of air-to-water heat pumps in the Greek climate

With the implementation of the European Union (EU) Energy-related Products (ErP) Directive, heat pumps (HPs) and in particular air-to-water heat pumps (AWHPs), are expected to be widely installed in heating systems of residential and of the tertiary sector buildings. Heat pumps are nowadays regarded as a key technology for achieving the EU strategy towards nearly Zero Energy Buildings (nZEBs) and for reducing the fossil primary energy consumption and the related CO2 emissions. The awareness of HPs seasonal efficiency, which is affected by multiple parameters, is very important for choosing the best heat pump technology and the right equipment in a heating or cooling installation. The aim of this paper is to provide the Seasonal Coefficient of Performance (SCOP) of various AWHPs available in the Greek market from various manufacturers and installed in buildings located in the four Greek climate zones (A, B, C, D). The calculations are performed according to EN 14825 by using temperature data of four representative cities, one for each zone. Numerical results show the influence of various parameters, like HP’s compressor technology, water outlet temperature, and weather compensation to SCOP value, and highlight the importance of climate data for the accuracy of seasonal performance estimation.

Predictive chiller operation: A data-driven loading and scheduling approach

The proper sequencing and optimal loading of chillers is one of the major avenues for energy efficiency improvement in existing heating, ventilating and air conditioning installations. The main enabler for the success of such applications is the access to accurate chiller performance maps that allow to operate the equipment in optimal conditions. However, current solutions are excessively reliant on maps obtained through suboptimal means, such as manufacturer datasheets, extensive instrumentation campaigns or burdensome modelling and simulation methodologies. Furthermore, recent studies show that strategies based on model-predictive control may lead to increased savings by anticipating the future cooling demand and scheduling the operation of the chillers, selecting the optimal operation configuration and extending the remaining life by reducing switching. In this regard, this study presents a novel data-driven and multi-criteria chiller orchestration strategy that combines a chiller performance characterization stage for obtaining performance maps based on a neural network-based learning methodology and a state-of-the-art hybrid load forecasting scheme for calculating the future load profiles. The effectiveness of the proposed methodology is tested with experimental data from a multi-chiller installation in a tertiary sector building, where nearly a 20% average performance increase is achieved compared to the standard real-time controller of the HVAC installation.

A multiperiod multiobjective framework for the synthesis of trigeneration systems in tertiary sector buildings

A multiperiod multiobjective framework for the synthesis of trigeneration systems in tertiary sector buildings

MULTICRITERIA OPTIMIZATION OF RENEWABLE-BASED POLYGENERATION SYSTEM FOR TERTIARY SECTOR BUILDINGS

This manuscript presents the bicriteria optimization of a polygeneration system to be installed in a tertiary sector building, considering economic and environmental objective functions. Electricity, hot water, steam, and cooling demands were considered. The bicriteria problem considered the annual costs and the annual carbon footprint. Updated environmental information was obtained through the application of the Life Cycle Assessment methodology and implemented within a Mixed Integer Linear Programming (MILP) model, along with economic and legal data. Solar photovoltaic energy and biomass were available, as well as natural gas and diesel. The energy system could import and export electricity to the electric grid. Individual optimal solutions were obtained from economic (annual costs) and environmental (annual carbon footprint) viewpoints were different, and the .constraint method was utilized to tackle these conflicting objectives. It was verified that significant reductions in annual costs could be obtained if the annual carbon footprint was partially compromised. A configuration based on one gas engine, two biomass boilers and three mechanical chillers was recommended, with an annual carbon footprint of 2,895,909 kg CO2-eq/year (approximately 570,000 kg CO2-eq/year less each year in comparison with the economic optimal) at a total annual cost of R$ 1,429,435.

Determination of a Building's balance point temperature as an energy characteristic

The building's balance point temperature represents the outdoor temperature at which no auxiliary energy is needed to ensure thermal comfort. Its estimation presents the main challenge of applying the degree day method for space cooling applications, since in addition to building thermal characteristics it also depends on internal and external heat gains. In this paper, a new approach for determining the instantaneous balance point temperature, based on an optimization-based grey-box modelling procedure, is presented. The developed grey-box model is built on an assumed functional dependency between the building thermal load and the power demand of its HVAC system. Its application requires only the use of basic building geometric parameters apart from the cooling electricity demand and corresponding meteorological data, which are utilized to estimate the model parameters using a derivate-free optimization procedure. Additionally, a new technique for visualizing and analyzing the behavior of the obtained instantaneous balance point temperature is introduced. The proposed methodology is verified on a set of artificially generated data, achieving an average prediction error of 5.2%, and its applicability demonstrated on a sample of real tertiary sector buildings. The results indicate that the presented methodology can be used to deduce building and corresponding HVAC system characteristics.

Operational performance of an Air Handling Unit: insights from a data analysis

Space heating and cooling is one of the most relevant causes of energy consumption in both residential and tertiary sector buildings. In particular, service buildings and offices are mostly served by all-air HVAC systems in which control logics are fundamental to guarantee reliability and performance. Building automation systems are therefore becoming more and more relevant as a support tool for reducing the energy consumption in these contexts. For this reason, the detailed analysis of operational data from real units can help in understanding the main variables that affect the performance and functioning of all-air systems. This paper presents some results from operation data analysis of an Air Handling Unit (AHU) serving a large university classroom. The main drivers of the energy consumption are highlighted, and the classroom occupancy is found to have a significant importance in the energy balance of the system. The availability of historical operation data allows performing a comparison between the actual operation of the AHU and the expected performance from nominal parameters. An example of fault detection is proposed, considering the operation analysis of the heat recovery unit over different years.

Evaluation of the performance gap in industrial, residential & tertiary near-Zero energy buildings

Energy efficiency, advanced controls and renewable energy systems for operating industrial, residential and tertiary sector buildings designed to be Near-Zero Energy are investigated to explore the performance gap. The analysis involves a comparison of energy dynamic and quasi-dynamic models with data from smart monitoring systems, indoor and outdoor environment measurements, power consumption and production data. Specific issues and conclusions have been drawn as the basis for addressing the performance gap between energy efficiency prediction in the design phase and measurements’ evaluation in operational phase.

Energy mapping of existing building stock in Spain

Energy performance certificate databases are a key tool for mapping national building stock and thus fostering greater overall energy efficiency. This paper presents an insight into the energy performance of residential and tertiary sector buildings in Spain, through an analysis of the first 129,635 energy performance certificates issued for existing buildings, collected by the Catalan Institute of Energy. Most of the residential buildings or building units that were studied were “E” class (53.6%). Single-family houses were found to use more energy on average (248.0 kWhp/m2) than individual dwellings (183.2 kWhp/m2). Tertiary sector buildings were found to have slightly better energy performance (26.4% of buildings were rated “D class”), with an average energy consumption of 317.8 kWhp/m2. Modern buildings consume less energy, as they must meet the higher energy performance requirements stated in thermal building regulations. Residential buildings or building units located in hotter climate zones consume slightly less energy than those located in colder zones, mainly because heating accounts for a high percentage of overall energy expenditure (70–75% in residential buildings). A significant proportion of the energy consumed in tertiary sector buildings is for lighting (37.2%). This research defines the current energy consumption baseline of existing buildings in Spain. The results can help to prioritize energy conservation efforts according to building type, construction period, climate zone and specific end-uses. They may also help public authorities to plan future energy policies, and construction practitioners to identify market segments and business strategies.

A building automation and control tool for remote and real time monitoring of energy consumption

Abstract Nowadays, buildings are responsible for about 40% of the EU's total final energy consumption and greenhouses emissions, putting them among the largest end-use sectors globally. In this context, a number of studies exist in the international literature analyzing the importance of effective energy and environmental management of the buildings. With respect to the above, the main aim of the paper is to present a building automation and control tool for remote and real time monitoring of energy consumption in the building sector. Apart from analyzing the building's energy profile, the tool integrates control scenarios that minimizes the energy consumption and rationalizes the energy use in the highest degree. The proposed tool achieves significant decrease in the operating cost of active system in a tertiary sector building, while maintaining desirable comfort.

Thermoeconomic analysis of a micro-CHP installation in a tertiary sector building through dynamic simulation

A thermoeconomic analysis has been applied to the annual operation of a micro-cogeneration installation in a tertiary sector building combining the capabilities of dynamic simulation with the thermoeconomic analysis. The SenerTec’s DACHS micro-cogeneration unit is considered integrated in a heating and domestic hot water installation, meeting the electric and thermal loads of a residential building. A six minute-based exergy analysis has been implemented in the TRNSYS v.16 thermal simulation software, while the Life Cycle Analysis (LCA) has been developed to determine the cumulative exergy consumption of the different components of the plant. The thermoeconomic analysis of the micro-CHP installation is performed for its annual operation which includes the analysis of the entire system, considering the costs and exergy content of both flows and components. The relationship between the annual contribution to the costs of the components and the energy consumption has resulted equal to 34.2%. A combined production cost value has been defined and has been compared with the micro-CHP unit and the conventional production system, being 34.6 and 45.42 c€/kWhex respectively, underlying the opportunity that micro-CHP units provide in residential installations.

Review on the European Strategies for Energy-Efficient Buildings

Reduction of the energy consumption in the building stock is an essential part of the sustainability strategies of the European Union on economy, environment and Climate Change. Operation and use of the residential and tertiary sector buildings are responsible for roughly 40% of the total final energy consumed in its Member States. This demand is supplied mainly from the imported fossil fuels. Energy-efficiency of buildings has grown to one of the main mechanisms in pursuits to alter the negative trends of growing consumption that would lead to an increase of the import dependence and increase of greenhouse gas emissions. In recent years, the European policy has shown signs of success but the targets seem to have been set as too ambitious. A review on the energy-efficiency strategies is presented in this paper in order to propose an explanation for the delay. It has been identified as insufficient links between statistics on the energy supply and the energy demand in various parts of the existing building...