Energy Storage In Buildings Research Articles

Cenosphere-based PCM microcapsules with bio-inspired coating for thermal energy storage in cementitious materials

Phase change materials (PCMs) provide passive storage of thermal energy in buildings to flatten heating and cooling load profiles and minimize peak energy demands. After microencapsulated into a protective shell, they can be directly added to cementitious materials to add thermal energy storage capacity to the material. However, existing studies show that the strength of the produced materials can be drastically reduced by the added PCM microcapsules. To overcome this drawback, this study develops a novel PCM microcapsule using the cenosphere as the protective shell, together with a bio-inspired dopamine coating. As hollow fly ash particles, cenosphere shells are much harder and stronger than commonly used polymer based protective shells. While the strong binding ability of dopamine to diverse surfaces through covalent and non-covalent interactions provides better bonding between the PCM microcapsule and the surrounding cement paste. For these reasons, the strength of the produced cement mortar can be greatly improved by this microcapsule. An experimental study shows that a 35% increase in compressive strength has been achieved by adding 10 wt% of the new PCM microcapsule into the cement mortar. Microstructure examination and hydration products analysis revealed that the dopamine coating facilitates the hydration of the cement and produces a denser and stronger interface between the microcapsule and the cement paste. As a result, a novel PCM microcapsule is developed which not only integrates latent heat storage capacity to the cement mortar but also enhance the compressive strength of the mortar, which cannot be achieved by any other PCM microcapsules.

Rethinking residential energy storage: GHG minimization potential of a Carbon Reinforced Concrete facade with function integrated supercapacitors

With the rise of sustainable energy generation, the need for integrated building energy storage solutions increases. Supercapacitors have not yet been considered a viable alternative to Li-ion batteries, often because of their space requirements. We present the function integration of supercapacitors into a facade, where space is abundant when using novel lightweight Carbon Reinforced Concrete (CRC) construction designs. We develop real prototypes. While materials and processes for the approach have been characterized for manufacturability in earlier studies, the resulting sustainability potential remains an open question. This study therefore assesses and supports the design process of that multifunctional facade with the help of Life Cycle Assessment (LCA). LCA results shall guide design choices on materials and constructional alternatives. We further elaborate on the potential of the multifunctional facade to compete with a Li-ion battery system as the current benchmark for residential energy storage. While the proposed design is still a prototype, the cradle-to-site LCA models a full-scale production to allow for that comparability. We calculate the greenhouse gas (GHG) minimization potential for the multifunctional facade with integrated supercapacitors. It is significantly lower by a factor of around 20 in comparison to Li-ion battery energy storage. We further use different functional units to interpret the LCA results, considering both the function of the facade and energy storage. Overall, results show that the choice of the functional unit affects the material and constructional recommendations.

Energy, environmental, and economic analysis of different buildings envelope integrated with phase change materials in different climates

Several technologies were been developed to store the solar energy for different applications especially in the construction sector. Integrating phase change materials (PCM) into building is one of the effective solutions for energy efficiency.This paper aims to evaluate the optimal envelope type and climatic zone able to improve the performance of buildings using PCM. A numerical simulation was conducted using the difference finite method by Energy plus, in three climates of North Africa; Mediterranean, arid and sub-arid climate, concerning four different building envelopes (brick, concrete block, reinforced concrete and earth) to analyze the energy, economic and environmental impact.The maximum values of energy saving rate is found in the arid and sub-arid climate, with the highest value of 10.5 % for earth envelope, and the lowest value of 2.57 % for concrete block envelope in Mediterranean climate. The use of PCM is more efficient for cooling in arid climate for the different considered envelopes with a maximum of cooling energy reduction of 7.3%, and its use in the sub-arid climate and the Mediterranean one is more efficient for heating with a maximum value of 10.7% in the earth envelope.The environmental and economic analysis shows that the use of PCM in optimal conditions can reduce 10 % of energy cost and 707 kg/year of CO2 emissions. Furthermore the payback period obtained varied between 7 and 43 years with an average of 23 years.Conclusively, the use of PCM for thermal energy storage in buildings still a good solution for energy performance.

Dynamic simulation and optimization of a novel energy system with Hydrogen energy storage for hotel buildings

In the current study, an innovative smart energy system based on hybrid solar-GT energies is proposed. Transient performance assessment and techno-economic analyses are conducted to evaluate the dynamic performance of the system. The system has three main parts: solar panels, a Hydrogen production and storage system and gas turbine system, a chiller, and several heat exchangers and auxiliary components. The goal is to set a stand-alone system to generate the need of the building, including heating, power, and cooling. The system is an off-grid system due to its energy storage system. The system is analyzed comprehensively from 3E standpoints. A parametric study of key design variables is performed, and optimization is carried out to find the best solution point. Results indicate that at the optimized point, the system reaches the effectiveness of 39.5%, the emission of 0.85 kg/kWh and the Levelized product cost of 0.051 $/kWh. Furthermore, increasing the pressure of the (absorption chiller) AC in the (gas turbine) GT cycle from 1.5 to 7.5 results in a sharp decline in net output work.

Investigation of a novel bio-based phase change material hemp concrete for passive energy storage in buildings

• Fabrication of a novel bio-based PCM hemp concrete by impregnation. • Hemp shives/CA composite was characterized using SEM, DSC and TGA techniques. • Melting temperature and enthalpy of the composite were 28.9 °C and 78.7 J.g −1 . • Promising thermoregulation ability of the PCM hemp concrete for building envelopes. In latent heat storage, energy is stored through the change of state of a material and then released when the material returns to its original phase. Latent heat thermal energy storage systems incorporate phase change materials (PCMs) as storage materials. The objective of this study is the fabrication and characterization of a biosourced PCM hemp concrete. Hemp shives are vacuum impregnated with CA with an incorporation rate of 53%. The resulting shape-stabilized hemp shives/CA composite is used to fabricate PCM hemp concrete. The morphology and thermophysical properties of the materials at all stages (from pure CA to hemp concrete PCMs) are characterized using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and compared to the reference state (hemp concrete without PCMs). Results of the DSC measurement indicated melting and solidification temperatures of hemp shives/CA composite of 28.9 °C and 23 °C, respectively and enthalpy of melting and solidification calculated as 78.7 and 76.4 J.g −1 , respectively. The TGA/dTG results showed that the form stable composite exhibits good thermal stability under 170 °C, making it suitable for building application. The thermal performances of PCM hemp concrete are evaluated in a climatic chamber and compared to those of a reference hemp concrete. Results showed a good thermoregulation capacity of the PCM hemp concrete with a maximum time shift of 30 min and a temperature difference between reference and PCM hemp concrete of about 4.6 °C. Featured Application: Passive latent heat storage for building applications, thermal comfort.

Development of a new composite material for building energy storage based on lauric acid-palmitic acid-paraffin ternary eutectic and expanded perlite

Building thermal energy storage is critical to global sustainability as building energy consumption rises. In this study, a lauric-palmitic acid-paraffin ternary eutectic (LPP) was prepared from lauric acid, palmitic acid, and paraffin, and this LPP eutectic was adsorbed into expanded perlite (EP) via vacuum adsorption method to form a composite phase change material (LPP/EP). Leakage tests show that the maximum loading rate of EP on LPP is 75 %. Then, the chemical structure, crystal structure, crystalline morphology, micromorphology, and thermal property of LPP/EP were evaluated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Polarizing Optical Microscope (POM), scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TG). The results show that LPP/EP has superior crystal and chemical compatibility, LPP/EP melts at 31.78 °C and absorbs 117.34 J/g of latent heat, and LPP/EP has good thermal stability. Meanwhile, LPP/EP exhibits better thermal storage performance than EP. In addition, the 1000 melting-solidifying cycling experiment indicates that the LPP/EP has excellent durability. Therefore, the LPP/EP composite phase change materials will have an amazing performance in the field of building thermal energy storage.

A Two-Level Model Predictive Control-Based Approach for Building Energy Management including Photovoltaics, Energy Storage, Solar Forecasting and Building Loads

This paper uses a two-level model predictive control-based approach for the coordinated control and energy management of an integrated system that includes photovoltaic (PV) generation, energy storage, and building loads. Novel features of the proposed local controller include (1) the ability to simultaneously manage building loads and energy storage to achieve different operational objectives such as energy efficiency, economic cost efficiency, demand response and grid optimization through the design of specific power trajectory tracking performance functionals, (2) an energy trim function that minimizes the impact of solar forecasting errors on system performance, and (3) the design of a state of charge controller that uses day-ahead forecast of solar power and building loads to intialize energy storage at the start of each day. The local controller is tested in simulation using an exemplary system with PV generation, energy storage and dispatchable building loads. Two sample days with different PV forecasts and multiple case scenarios are considered, and the performance of the algorithm in managing the real and reactive net building load trajectories and the ramp rate of PV injections into the utility network are evaluated. The simulations are based on actual forecasted and measured PV data, and the results show that the local controller meets the tracking requirements for real and reactive power within the operating constraints of the building.

Seismic resilience of extra-large LNG tank built on liquefiable soil deposit capturing soil-pile-structure interaction

Assessment of seismic resilience of critical infrastructure such as liquefied natural gas (LNG) storage tanks, is essential to ensure availability and security of services during and after occurrence of large earthquakes. In many projects, it is preferred to build energy storage facilities in coastal areas for the ease of sea transportation, where weak soils such as soft clay and loose sand with liquefaction potential may be present. In this study, three-dimensional finite element model is implemented to examine the seismic response of a 160,000 m3 full containment LNG tank supported by 289 reinforced concrete piles constructed on liquefiable soil overlaying the soft clay deposit. The seismic soil-structure interaction analysis was conducted through direct method in the time domain subjected to the 1999 Chi-Chi and the 1968 Hachinohe earthquakes, scaled to Safe Shutdown Earthquake hazard level for design of LNG tanks. The analyses considered different thicknesses of the liquified soil deposit varying from zero (no liquefaction) to 15 m measured from the ground surface. The key design parameters inspected for the LNG tank include the acceleration profile for both inner and outer tanks, the axial, hoop and shear forces as well as the von Mises stresses in the inner tank wall containing the LNG, in addition to the pile response in terms of lateral displacements, shear forces and bending moments. The results show that the seismic forces generated in the superstructure decreased with increasing the liquefied soil depth. In particular, the von Mises stresses in the inner steel tank exceeded the yield stress for non-liquefied soil deposit, and the elastic–plastic buckling was initiated in the upper section of the tank where plastic deformations were detected as a result of excessive von Mises stresses. However, when soil liquefaction occurred, although von Mises stresses in the inner tank shell remained below the yield limit, localised stress concentrations were observed in the lower section of the tank near the base, increasing the risk of the elephant foot buckling. The lateral displacements, shear forces and bending moments in the piles increased with increasing depth of the liquefied soil. Indeed, increasing the pile lateral displacement amplified the bending moment at the pile head, thus resulting in increases in the pile bending moments especially when the liquefied soil depth exceeded one third of the entire soil deposit. In particular, the bending moment at the pile head exceeded the yield moment capacity of the pile and subsequent plastic hinges were formed. Moreover, when the thickness of the liquefied soil was more than half of the entire soil depth, the mobilised bending moments in the piles exceed the ultimate moment capacity of the pile and thus total failure of the piles were observed. In addition, in the absence of liquefied soil layer, the inertial interaction had a dominant impact on the pile response in this study. However, with increasing the thickness of the liquefied layer, further loads were developed in the piles due to amplified kinematic interaction, while the inertial interaction-induced loads decreased.

A novel dodecanol/tepexil PCM composite for thermal energy storage in buildings

Phase change materials for thermal energy storage through latent heat have been extensively investigated in the last decade for their high potential for heating and cooling purposes in buildings. This paper presents a novel composite PCM's thermophysical properties formed by dodecanol/tepexil and prepared by the vacuum impregnation technique. Although there have been some past studies on making PCM composites using dodecanol, their enthalpy values have not been as high as expected. Scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), laser flash analysis (LFA), differential scanning calorimetry (DSC), and T-History measurements were used to characterize the PCM composite. Dynamic T-History tests revealed that this PCM Dodecanol/Tepexil composite has a fusion temperature of 24.13 °C and a fusion enthalpy of 118 J g−1 and solidification temperature of 20.41 °C with a solidification enthalpy of 108.35 J g−1. These results are the highest values using impregnation techniques to date in the thermal comfort range that goes from 21 to 26 °C for a mild-tempered climate, where the mean temperature is about 22 °C and high annual thermal oscillations (where PCM or high thermal inertia materials are recommended), as far as the authors are concerned. The resulting thermal conductivity of the dodecanol/tepexil composite was 0.308 W m−1 K−1 at 30 °C. Tepexil particles of less than 250 μm exhibit an average pore size of 9.5, 36, and 250 nm and a BET surface area of 2.1 (m2 g−1). Leakage tests on the composite showed a maximum retention rate of 40% dodecanol. It was concluded that this PCM composite dodecanol/tepexil could be considered good candidate material with the potential for energy storage in building applications due to its thermal/chemical stability and high energy storage performance.

Characterization of Fly Ash Cenosphere – Capric acid composite as phase change material for thermal energy storage in buildings

ABSTRACT Energy demand in buildings has been steadily increasing in the recent past. The majority of energy is used to heat and cool the building envelope to maintain a conducive thermal environment for habitation. Integration of Phase Change Materials (PCM) in buildings has improved the structure’s energy efficiency by absorbing and discharging energy as latent heat. In this work, Cenosphere–Capric Acid (CeCA) composite PCM was developed by the technique of impregnating capric acid (CA) into the hollow core of the cenosphere (Ce) under vacuum followed by sealing it with SiO2. The morphology of the prepared CeCA composite was investigated by FESEM. Mineralogical characterization by XRD suggested that the mineral structure of the CeCA composite has remained unaltered. Phase change temperature and latent heat of CeCA composite were evaluated as 27.60°C and 69.07 J/g for melting and 23.16°C and 71.30 J/g for freezing, respectively. Thermo-Gravimetric Analysis (TGA) of CeCA indicated the enhanced thermal stability of the composite. CeCA composite indicated good chemical compatibility between Ce, CA, and SiO2; hence, the composite is chemically stable, as revealed by FTIR analysis. Accelerated thermal cycling of CeCA composite indicates a relatively modest change in phase change temperature of 0.6°C for melting and 0.1°C for solidification. Further characterization by TGA and FTIR, suggested that the CeCA composite is reliable for the long term. It implies that the CeCA composite has significant potential as a PCM for thermal energy storage application in construction materials and structures.

A high-performance intermediate-temperature aluminum-ion battery based on molten salt electrolyte

Non-aqueous rechargeable aluminum-ion batteries (AIBs) are a promising candidate for grid-scale energy storage due to their high theoretical energy density, safety, environmental benignity, and the abundance of Al sources. However, the limited cathode capacity and the high price of ionic liquid electrolytes hinder their large-scale applications. Herein, an intermediate-temperature AIB composed of nickel disulfide-based cathode and NaCl-AlCl3-Al2S3 molten salt electrolyte is reported. A highly reversible conversion mechanism between Ni3S4 and Ni during cycling is proved with cathode capacities exceeding 500 mAh g−1. The full cell delivers a cathode capacity of 320 mAh g−1 at 240 °C and a current density of 2000 mA g−1 with negligible capacity fade after 2000 cycles. The raw material cost is estimated to be as low as 28 $ kWh−1 based on the electrode and electrolyte materials. The molten salt electrolyte-based AIB provides promising opportunities to build energy storage systems with low cost, high safety, stable electrochemical performance, and long lifetime.

Coupled Heat Power Operation of Smart Buildings via Modular Pumped Hydro Storage

Abstract In the United States, building sector is responsible for around 40% of total energy consumption and contributes about 40% of carbon emissions since 2012. Within the past several years, various optimization models and control strategies have been studied to improve buildings’ energy efficiency and reduce operational expenses under the constraints of satisfying occupants’ comfort requirements. However, the majority of these studies consider building electricity demand and thermal load being satisfied by unidirectional electricity flow from the power grid or on-site renewable energy generation to electrical and thermal home appliances. Opportunities for leveraging low-grade heat for electricity have largely been overlooked due to impracticality at small scale. In 2016, a modular pumped hydro storage technology was invented in Oak Ridge National Laboratory, named Ground Level Integrated Diverse Energy Storage (GLIDES). In GLIDES, employing high-efficiency hydraulic machinery instead of gas compressor/turbine, liquid is pumped to compress gas inside high-pressure vessel creating head on ground level. This unique design eliminates the geographical limitation associated with the existing state-of-the-art energy storage technologies. It is easy to be scaled for building level, community level, and grid level applications. By using this novel hydro-pneumatic storage technology, opportunities for leveraging low-grade heat in building can be economical. In this research, the potential of utilizing low-grade thermal energy to augment electricity generation of GLIDES is investigated. Since GLIDES relies on gas expansion in the discharge process and the gas temperature drops during this nonisothermal process, available thermal energy, e.g., from thermal storage, combined cooling, heat and power system (CCHP), can be utilized by GLIDES to counter the cooling effect of the expansion process and elevate the gas temperature and pressure and boost the roundtrip efficiency. Several groups of comparison experiments have been conducted, and the experimental results show that a maximum 12.9% cost saving could be achieved with unlimited heat source for GLIDES, and a moderate 3.8% cost improvement can be expected when operated coordinately with CCHP and thermal energy storage in a smart building.

Development of a shape-stabilized phase change material utilizing natural and industrial byproducts for thermal energy storage in buildings

A comprehensive study was conducted to develop and utilize a novel shape-stabilized phase change material utilizing two abundantly available and low-cost natural materials, namely scoria and expanded perlite and an industrial byproduct, heavy oil ash, in combination with polyethylene glycol. The thermal and energy storage characteristics of the composite materials were evaluated with the aim of using them to conserve energy in the domestic facilities. The results of differential scanning calorimetry showed that expanded perlite composite has the highest melting and solidification latent heat values, 150.7 J/g and 134.6 J/g, respectively, compared to scoria and oil ash composite. However, expanded perlite composite has lower thermal conductivity compared to other composites. Consequently, a novel system incorporating carbon nano tubes (0.5 wt.% and 1 wt.%) in the expanded perlite composite was developed to improve its thermal conductivity. The thermal conductivity (0.453 W/m.K) of the new system with 0.5% carbon nano tubes is remarkably more than that of commonly used phase change materials. Further, the developed PCM with 0.5% carbon nano tubes can transform sunlight into thermal energy with a solar-to-thermal energy conversion efficiency of 59.4% and it has a thermal conductivity that is 97% more than that of polyethylene glycol alone. Besides, the newly developed PCM also shows excellent energy storage and release performance. All these favorable characteristics indicate that the developed phase change material can be beneficially utilized in thermal storage systems.

Feasibility analysis and feature comparison of cold thermal energy storage for off-grid PV air-conditioned buildings in the tropics

Cold thermal energy storage (CTES) is a cost-efficient storage approach for PV powered air-conditioning systems in tropical buildings. However, the feasibility and performance of different CTESs, including chilled water storage, ice storage, PCM cooling storage, and building thermal storage, are still unclear for off-grid PV air-conditioned buildings.In this study, an off-grid PV system with battery and CTES is proposed, including the operation strategy to manage the energy-storage process. To implement all CTES-types, a co-simulation model, which integrates the system model with the ARX (autoregressive with exogenous input) cooling-load model, is constructed to enable the interaction between supply- and demand-side. Based on the minimization of net present cost and the constraint of a certain required solar fraction, an optimization method is developed to find the optimal system-configuration. Moreover, an office, a hotel, and a residence are selected for a case study.The results indicate that CTES is feasible for higher solar fraction. The feasibility ranking of building type is (from high to low): residence, hotel, and office. In the most suitable case (residence), the maximum reduction of system costs (compared to battery-only system) is 49.76%, 41.77%, 44.31%, and 22.78%, respectively, for chilled-water storage, ice storage, PCM cooling storage, and building thermal storage. These values are 22.48%, 12.00%, 17.42%, 2.60% for the hotel, and 19.26%, 11.57%, 13.64%, 4.06% for the office. In addition, the sensitivity analysis shows that the increasing cost of both PV-array and CTES-device affects the feasibility of CTES negatively, while the increasing battery cost is a positive factor. Compared to the cost of the PV-array and the CTES-device, the battery cost represents the most significant effect-factor for feasibility.

Correction: Addressing energy storage needs at lower cost via on-site thermal energy storage in buildings

Correction for ‘Addressing energy storage needs at lower cost via on-site thermal energy storage in buildings’ by Adewale Odukomaiya et al., Energy Environ. Sci., 2021, 14, 5315–5329, DOI: 10.1039/D1EE01992A.

Application of phase change energy storage in buildings: Classification of phase change materials and packaging methods

Phase change energy storage plays an important role in the green, efficient, and sustainable use of energy. Solar energy is stored by phase change materials to realize the time and space displacement of energy. This article reviews the classification of phase change materials and commonly used phase change materials in the direction of energy storage. Commonly used phase change materials in construction and their packaging methods are listed according to the properties of phase change materials. Through different packaging methods to enhance heat exchange, this work solves the problem of material leakage and summarizes the advantages and disadvantages of those methods through comparative analysis. The impact of macro-encapsulation and micro-encapsulation on material encapsulation are also outlined. The simulation and model construction methods of different packaging methods are reviewed. This research is dedicated to the comparative analysis of the selection of phase change materials and packaging methods in buildings a to actively promote the promotion and application of phase change energy storage in buildings.

Performance Improvement of Lauric Acid-1-Hexadecanol Eutectic Phase Change Material with Bio-Sourced Seashell Powder Addition for Thermal Energy Storage in Buildings

Performance Improvement of Lauric Acid-1-Hexadecanol Eutectic Phase Change Material with Bio-Sourced Seashell Powder Addition for Thermal Energy Storage in Buildings

Thermo-regulating performance of concrete slab loaded with shape stabilized phase change material in tropical climate

The building overheating problem is one of the most important problems facing all over the world. Various methods like using highly thermal resistive building materials, composite building materials were used to reduce the heat gain of the buildings. One of the method which can be used in place of traditional methods is using building elements with high thermal energy storage capacity. The significance of this study is to improve the thermal energy storage capacity of the building element for improving indoor thermal performance of the building. In this study latent heat energy storage capacity of the concrete slab is enhanced by incorporating Shape Stabilized Phase Change Material (SS-PCM) in it. SS-PCM was prepared by incorporating eutectic PCM (Paraffin Wax 70% and Coconut Oil 30%) in highly porous material called zeolite. The zeolite powder successfully incorporate 30 wt% PCM without showing any leakage at elevated temperature. Morphology of the SS-PCM was evaluated through Scanning Electron Microscopy (SEM) images. The SS-PCM at 0 wt%, 10 wt%, 20 wt%, and 30 wt% was used to prepare composite concrete slab by replacing fine aggregates. Composite concrete slabs were tested for indoor thermal behavior in real outdoor testing of 72 h. Indoor thermal performance was evaluated on the basis of peak temperature reduction, thermal amplitude, time delay, and decrement factor. The 30% SS-PCM has a high latent heat capacity, which significantly improves thermal energy storage in buildings. Various parameters like peak temperature reduction, time lag, thermal amplitude and decrement factor were evaluated. Concrete slab integrated with 30% SS-PCM shows maximum peak percentage temperature reduction of 10.04 % and percentage reduction in thermal amplitude of 23.71 % in comparison to conventional concrete. Additionally, infrared thermography of all the concrete slabs at different time of the day was done.

Experimental investigation of clay brick with sensible, latent, and hybrid thermal energy storage in buildings

Global warming has caused uneven extremities in the climate such as heat waves, floods, and extreme rise in temperatures. Consequently, there is increase in demand for energy for indoor space cooling in the buildings to create better indoor thermal comfort. Thermal energy storage (TES) using Phase Change Material (PCM) is an effective technology for improving the thermal performance of the building envelope. Energy efficient building envelope can reduce the external heat gain and maintains indoor thermal comfort level easily. In this study, the thermal performance of clay bricks integrated with sensible heat storage material, latent heat storage material, and hybrid (sensible + latent) was investigated. A comparative study of indoor thermal performance in terms of peak temperature, thermal amplitude, time lag, decrement factor of sensible heat storage brick, latent heat storage brick, and hybrid brick in comparison with conventional brick was prepared. Latent heat storage brick has shown the highest percentage average peak temperature reduction of 3.86 % in comparison to conventional brick. Maximum reduction of 13.74 % was shown by latent heat storage brick followed by hybrid heat storage brick and then by sensible heat storage brick. Time lag of 180 min is observed in brick embedded with latent heat storage capacity. Additionally, infrared thermal images suggest that the brick integrated with latent heat storage material shows better indoor thermal performance.

Environmental Analysis of Integrating Photovoltaics and Energy Storage in Building

The energy consumption of buildings accounts for approximately 36 % of the final energy consumption in Europe, being the largest end-user. The UK government has committed to cut greenhouse gas (GHG) emissions by 100 % below 1990 levels and bring all GHG emissions to net-zero by 2050.To support the realisation of these goals the concept of an Active Building was formulated which refers to any building type, such as factories, offices, homes, and other structures in the built environment, which are equipped to conserve, generate, store, and release energy. The increasing deployment of rooftop photovoltaics drives the growth of energy storage to capture solar energy for later use in buildings. The Active Office was built at Swansea University, UK in 2018 and is a two-story office building. Its energy demand, including that of electric vehicle charging, is primarily met by the 23 kWp of building-integrated photovoltaics (BIPV) and 110 kW of lithium-ion (Li-ion) batteries. When the BIPV and batteries are unable to meet the demand, electricity supplied from the grid can be used.The objective of the research is to assess the potential environmental impacts of the building energy system of BIPV and Li-ion batteries, as well as to address the lifetime and degradation of Li-ion batteries, and the associated consequences. Life cycle assessment (LCA) is employed in this research. Three operational strategies are designed regarding the interactions between the electrical grid, BIPV, and Li-ion batteries. In the best case operational scenario, using a rolling average to predict building generation and consumption, the GWP from the building operation is 33 g/kWh which is a 5 fold reduction compared with the grid emissions of 170 g/kWh. The worst case building operational strategy creates emissions of 128 g/kWh, it is still an improvement upon electricity supply by the national grid alone. This analysis demonstrates that operational strategy optimisation can reduce the environmental impacts of the Active Building concept compared with using grid electricity alone.