Internal Thermal Conditions Research Articles

Solar Radiation Impact on Interior Pressure and Temperature of LPG Storage Tank in Baghdad Provence

This work is related to reducing the impact of incident solar radiation on the internal thermal conditions of the LPG tank. An experimental study was carried out to test the effectiveness of using new thermal insulation layer for liquefied petroleum gas (LPG) tanks to reduce the absorbed heat during the summer season in Baghdad. Semi-spherical perlite particles of size (0.1861 to 1.604 mm) were mixed homogeneously with the resin coating is used as the heat insulating layer. Two identical thermally insulated and non-insulated LPG tanks are tested to indicate the effect of the adopted thermal insulation under different operating conditions. The two tanks were field tested with LPG volumetric filling ratio of (80%, 70%, 50%, 20%) and exposed to the same environmental conditions. Experimental results indicated that the coating significantly reduced the increase in temperature and pressure in the tanks, thus ensuring effective protection for the tanks. Where the results showed that the approved thermal coating prevented an increase in temperature and pressure in the insulated tank by (18.6%, 25%), respectively, compared to the non-insulated tank in July 2022. The data obtained confirmed the improvement in the safety of LPG storage, meaning that the thermal coating It is an effective way to improve the storage and transportation of liquefied gas in hot summer days.

Performance analysis and optimization of a zero-emission solar-driven hydrogen production system based on solar power tower plant and protonic ceramic electrolysis cells

The solar-driven high-temperature steam electrolysis is promising for efficient large-scale H2 production. In this study, a comprehensive component-to-system model and optimization framework is developed to investigate the performance of a zero-emission H2 production system based on solar power plant and protonic ceramic electrolysis cell. Compared to previous system studies, the detailed description of cell internal operating characteristics is realized by integrating multi-physics simulation and artificial neural network. After parametric analyses, it is found that the system energy/exergy efficiency and co-generation performance are complicated by each subsystem. And the optimal system performance (ηth = 50.63 %, Z = 179.63 $·h−1 and ηex = 33.03 %, Z = 178.94 $·h−1, with LCOE = 0.172 $·kWh−1 and ZH2 = 6.497 $·kg−1) is obtained considering cell operating features and system energy-exergy-economic factors through multi-objective optimizations. Besides, the tradeoff between system maximum H2 production capacity and cell internal thermal conditions is revealed. This study can facilitate the development of zero-emission green H2 production driven by renewable energy.

Thermal Performance Analysis of Affordable House in the Equatorial Coastal Area of the Tropics

Affordable housing subsidised by the government in Indonesia often poses many problems, including an uncomfortable internal environment that leads to the massive use of mechanical ventilation. Designing an affordable house undoubtedly faces challenges due to the very small building lots, while it should provide many spatial needs and functions for the occupants’ daily activities. Because of limited funding provided by the government, affordable house design is often based only on basic needs, thus scarcely considering thermal comfort for the occupants. This study evaluates the thermal performance of affordable houses built for the 2018 great earthquake, tsunami, and liquefaction victims in Palu’s coastal area. Field measurements were conducted in an affordable housing complex, and a sample house was selected, representing a raised floor house design prototype. External and internal climate conditions were recorded for nine days to establish the hourly thermal trend. Hobo Onset H21 microclimate stations were used to record external climate conditions, whereas Onset Hobo U12-012 T-RH-Light was employed to record internal thermal conditions. The result showed that the thermal condition in the sample house was intolerably hot. The main cause of these conditions is the design of the roof and building envelope. The selected materials with a high U-value also worsen the thermal conditions in the sample house

To Shade or not to Shade (and how)? Annual heating energy balance and internal temperature in low energy houses in Wrocław, Poland.

One of the important areas of occupant–building fabric interaction with IEQ consequences is windows’ shading. The relevance of shading has been explored through modeling studies in the context of energy, daylighting and thermal comfort, typically aiming to inform the design stage. In owner occupied housing the architectural design sets the scene for subsequent residents’ decisions concerning windows treatment. Here, based on varied treatments for 20m2 living room window observed during an in-depth building performance evaluation in same homes, dynamic modeling in TRNSYS is used to establish the related heating loads and internal temperatures. The results allow to rank five shading usage scenarios for three physical settings, namely lack of shading, external blind and internal curtain on lower half of the window, in terms of their overheating mitigation potential, based on simplified assumptions for heating, ventilation and shading practices. The modelling points towards severe overheating issue and crucial impact of shading usage patterns on its mitigation. Yearly modelled share of overheating hours (>26 °C) are almost double for unshaded scenario compared to the most effective shading strategy (25% and 13%). The simulation contributes to understanding of the field monitoring results where the unshaded living rooms experience more severe overheating, and the two shading settings in place are associated with comparable internal thermal conditions, respectively 22% vs. 5% and 6% of yearly share of overheating hours. The simplification of human-HVAC-building interaction model likely obfuscates solar heat gain control contribution to heating load.

Temperature behavior of cable-stayed bridges. Part I — Global 3D temperature distribution by integrating heat-transfer analysis and field monitoring data

Varying temperatures significantly affect long-span cable-stayed bridges. However, quantitative studies on their temperature behaviors are limited. Existing studies focus on 2D or 3D models of bridge segments only, exclude cables from heat-transfer analysis, and utilize inaccurate environmental conditions. For the first time, this study comprehensively and accurately investigates the global 3D temperature distribution of long-span cable-stayed bridges by integrating the heat-transfer analysis and field monitoring data. A navigation channel bridge of the Hong Kong‒Zhuhai‒Macao Bridge is used as the testbed. A global 3D refined finite element model of the entire bridge is established. The external thermal boundary conditions of the outer surfaces of the structure are carefully determined based on the real-time ambient temperature, wind, and solar radiation, which are tailored for each surface to reflect the influence of the geometric configuration. The internal thermal boundary conditions of the inner surfaces of the box girder and tower are dependent on the measured ambient temperature, considering the vertical temperature difference of the girder and the uniform temperature inside the tower. Then, the numerical heat-transfer analysis and field monitoring data are integrated to calculate the detailed temperature distribution of the entire bridge in different seasons. Results show that ambient temperature, wind, and solar radiation significantly affect the temperature distribution. For the girder, the vertical temperature difference is significant throughout the year, and the transverse temperature difference is nonnegligible in winter and summer, while the longitudinal temperature difference is trivial. The internal temperature of the tower remains stable owing to the insulation of the concrete. The temperatures of the cables vary from each other, which may cause stress redistribution within the structure. The calculated temperatures are in good agreement with their measured counterparts. The temperature results will be used to calculate the thermal-induced responses in the companion paper in a unified manner.

Effects of external ambient temperature at loading, journey duration and flock characteristics on the dead-on-arrival rate in broiler chickens transported to slaughter in Great Britain

Broiler mortality during transport and lairage, prior to slaughter, has negative welfare and economic implications. Knowledge of the factors affecting the dead-on-arrival (DOA) rate can help identify risk-mitigating strategies. The objectives of this study were to determine the DOA rate in broiler chickens transported to slaughter in Great Britain and associated risk factors. Requested data for all loads of broilers transported to slaughter by 5 large British commercial companies on 57 randomly-selected dates in 2019 were obtained and combined with weather data extracted from the Met Office MIDAS Open database. The DOA rate was described overall and per load using summary descriptive statistics. Mixed-effects Poisson regression was used to evaluate considered flock-, journey- and weather-related risk factors. Results were reported as incidence rate ratios (IRR) and 95% confidence intervals (CI). On the selected dates, 25,476 loads transported 146,219,189 broilers to slaughter. The overall mean DOA rate was 0.08%. The median DOA rate per load was 0.06% (interquartile range 0.03-0.09%; range 0.00-17.39%). Multiple risk factors were identified including loading temperature and catch method. At relative humidity ≤80%, the DOA rate was 16.89 (95% CI 15.25-18.70, P < 0.001) times higher for loads loaded in external ambient temperatures >30.0°C compared to those loaded in temperatures between 10.1°C and 15.0°C. When relative humidity was >80%, there was a 43% increase in DOA rate for loads loaded in temperatures below freezing compared to those loaded in temperatures between 10.1°C and 15.0°C (IRR 1.43, 95% CI 1.35-1.52, P < 0.001). The DOA rate was 32% higher for loads caught mechanically compared to those caught manually (IRR 1.32, 95% CI 1.23-1.42, P < 0.001). The overall DOA rate was lower than that previously reported in Great Britain and for other European countries. Most identified risk factors had a marginal effect, however, loading temperatures >30°C substantially increased DOA rate. Internal thermal environmental conditions were not evaluated. Avoidance of loading during periods of hot weather would improve the welfare of, and reduce economic losses in, broiler chickens.

Electricity peak load reduction of a refrigerator using phase change material

Phase change material (PCM) has become a topic of study in thermal management, as it has a high-energy storage density. Most refrigerators have a fixed-speed compressor, which operates randomly (on/off) during their cycle. This leads to a high-power peak of electricity when the refrigerators start at the same time. Therefore, this study aims to investigate the reduction potential of the power peak and energy consumption of a refrigerator using PCM as a heat absorber. Nine testing conditions were performed by using water as the internal thermal load, at 1, 2, and 3 kg. Besides, each internal thermal load condition was varied with a PCM mass of 500, 1,500, and 2,500 g. The necessary data, such as the internal temperature and power of a refrigerator and the outside ambient temperature, were collected. The results show that the mass of PCM significantly affected the peak power of the refrigerator and energy consumption. Moreover, the results clearly show that the PCM can be used to reduce the peak power and energy consumption of the refrigerator. The correlation of the power, related to the mass of the internal heat load, and the mass of PCM was also reported. The conclusion of this study is that the PCM is suitable for reducing the peak power and energy consumption of a household refrigerator.

ANALYSIS OF THE INFLUENCE OF THE INTERNAL HEAT CAPACITY OF A PUBLIC BUILDING ON THE THERMAL COMFORT PARAMETERS OF THE PREMISES DURING THE OPERATION OF THE HEATING SYSTEM IN ALTERNATING MODE

In the climatic conditions of Ukraine, which are characterised by a long heating period, considerable energy requirements for heating lead to an increase in energy efficiency requirements. A substantial reduction in the energy consumption of buildings while ensuring comfort conditions will be facilitated by the inclusion of a model of human thermal comfort in the complex “heat source – fencing” system. The purpose of this study was to find the factors affecting the internal heat capacity and, accordingly, the thermal inertia of the building and further take these factors into account upon assessing the thermal condition and parameters of thermal comfort of building rooms. The object of this study was the educational and administrative building of the National University of Life and Environmental Sciences of Ukraine. Many studies were carried out, namely full-scale measurements of heat flows and temperatures on the surfaces of samples of the building’s wall structure were carried out in a special climate complex that allows artificially creating external and internal thermal conditions of premises. It was found that the insulation of the structure with a layer of expanded polystyrene PSB-15, 100 mm thick, reduces heat losses through the wall panel by almost half. An algorithm for controlling the heat release process was developed, considering the internal heat capacity of the building. Compared to the “linear” dependence, this allows more accurately adjusting the schedule of heat carrier release to the heating system of a public building during the introduction of the alternating mode of its operation. The temperature deviation range is reduced by 4–6 °C, which allowed saving up to 10-12% of the consumed heat energy for the heating needs of the research object, provided that the normalised values of the internal temperature of the premises are maintained. Intermittent operation of the heating system of public buildings, the expediency of which is justified in this study, can be recommended for implementation in the structures of higher educational institutions of Ukraine.

Numerical prediction of tropical cyclogenesis. Part II: Identification of large‐scale physical processes under the monsoon shear line synoptic pattern

AbstractThis is the second part of a two‐part study to investigate the numerical prediction of tropical cyclogenesis. Part I presents a comprehensive statistical assessment of the performance of the high‐resolution European Centre for Medium‐Range Weather Forecasts deterministic forecasts in predicting tropical cyclone (TC) genesis over the western North Pacific between 2007 and 2018 using The International Grand Global Ensemble data. Among these forecasts, the ones that predict TC genesis occurring in the monsoon shear line synoptic pattern have the highest 5‐day predicted skill. In this article (Part II), the large‐scale dynamic and thermodynamic variables associated with this type of genesis are examined to identify the physical processes likely responsible for TC genesis. Moist convection appears to be one of the first important factors. Deep convection at the initial time (Day −5) is concentrated near the inner core of the pre‐genesis vortex. In the lower troposphere, the northeasterly flow to the north and southwesterly flow to the south of the pre‐genesis vortex begin to strengthen at Day −4 and Day −3 respectively, and then the maximum wind centres move close to the genesis position (GP) from Day −3 to Day 0. Strong low‐level radial wind and the associated absolute angular momentum (AAM) import develop on Day −4, which effectively forces a transverse circulation and spins up a surface vortex near the GP. The vertical gradients of latent heat release and the decrease in mean‐sea‐level pressure by Day −3 further support the import of low‐level AAM and the development of the low‐level vortex. At the upper levels, an anticyclone moves close to the GP, reducing the vertical wind shear at Day −2, fully establishing the secondary circulation system. The positive feedback between the environmental flow and the internal thermal forcing conditions from Day −2 to the genesis time are also important to genesis.

Application of Cold Radiant Surfaces in the Buildings Development in Summer Conditions

This paper presents a numerical study of sustainable energy application in the buildings construction using cold radiant surfaces in summer conditions. The study is made in a University building and the proposed technology is used to improve the internal thermal comfort conditions in summer conditions. This numerical study uses a software that simulates the whole Building Dynamic Response with complex topology in transient conditions. The numerical model is founded on the balance of energy and mass integral equations. The energy balance integral equations are taken for the indoor air of the compartments, the transparent (windows) bodies of the building, the interior and surroundings bodies of the building and the opaque (walls and doors) bodies of the building. The mass balance integral equations, taken into consideration for the water vapor and the air contaminants, are developed for the spaces of the buildings and the solid matrix (opaque and interior bodies). The software is used to assess the human thermal comfort and indoor air quality levels, the cold radiant system, indoor thermal variables, and other parameters. The building analyzed in this work has 107 compartments, of which 33 are for classes. The radiant system is based on the use of subterraneous cold water. Three situations were analyzed: without cold radiant surfaces, with horizontal cold radiant surfaces and with all compartment cold radiant surfaces. The thermal comfort level, using the Predicted Mean Vote (PMV) index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. The results demonstrate that the implemented Heated Ventilation and Air Conditioned system, working in Ventilation and Radiant methodology, with the use of all surfaces equipped with a cold radiant system, allows to guarantee, in the morning, acceptable, and, in the afternoon, near acceptable levels of thermal comfort by PMV index values according to category C of the standard ISO 7730. During occupancy, the indoor air quality levels obtained in the compartments are near the acceptable limit provided by the ASHRAE 62.1 standard.

A novel interconnect design for thermal management of a commercial-scale planar solid oxide fuel cell stack

Solid oxide fuel cell (SOFC) is a promising technology for stable power supply with high efficiency and high quality heat utilization, but it still faces the technical challenge of low long-term durability caused by thermal imbalance of its stack. An effective, novel thermal management method is urgently required for its market deployment. This study proposes a novel interconnect design for effective thermal management and elucidates the influence of its design variables on internal thermal conditions and heat transfer characteristics of a 1-kW planar SOFC stack. Three-dimensional thermo-fluid simulations are performed on the new stack design employing the novel interconnect and the conventional stack design for comparison. The new design is developed for the purpose of uniform in-plane (horizontal) temperature distribution by modifying the displacement of gas manifolds. At the repeating-unit scale, due to the reduced thermal resistance for horizontal heat transfer of the new stack, its in-plane temperature deviation decreases by 35–60 °C. At the stack scale with 30 unit-cells stacked vertically, the average temperature increases by 30 °C, and the vertical temperature difference decreases by 50 °C. Such thermal fields are the combined results of reduced gaseous convection and enhanced vertical solid-phase conduction through each repeating unit. In the new stack, the amount of heat transferred to the gas within each repeating unit is generally decreased, but is recuperated by increasing solid conduction through metallic interconnects. The relatively weakened gaseous heat transfer of the new design provides more thermal load at the lowest unit of the stack than the reference design, which promotes gas pre-heating prior to reaching the unit-cells and hence results in the elevated stack temperature. Such gas pre-heating also reduces the temperature difference in the vertical direction of the new design. The lower temperature differences both in horizontal and vertical directions enable the new stack to reduce its thermal imbalance and potentially to improve long-term durability.

Research on Indoor Thermal Environment of Building Corridor Based on Numerical Simulation

As an important connecting structure between modern buildings, because of its closed structure and high frequency of people’s passing, the local “greenhouse effect” formed by solar radiation causes strong discomfort to human body during the summer in northern China. In this paper, a building corridor in Tianjin is modelled by CFD, and the internal environment of the building corridor is simulated by turbulence model, heat transfer model and radiation model. It is found that K - ε model and DO radiation model in the numerical method can be used to simulate the internal thermal environment and solar radiation conditions of the building corridor. According to the distribution of air temperature and velocity in the corridor, a new type of building should be proposed in further study.

Stress Calculation and Analysis of a 600MW Supercritical Boiler’s Steam-water Separator

The steam-water separator of a 600MW boiler has been chosen as the research object. By theoretical analysis’s method and finite element analysis, the stress and secure research has been carried out in the steam-water separator as the thick-walled pressure vessel. For its start-up and normal operation of the working process and features and considering the internal pressure load and thermal stress loading conditions, the initiation of separation stress and security analysis have been carried out about the steam-water separator. The primary stress at the continuum of the cylinder structure can be calculated by the formula, and the calculated results are basically in agreement with the simulated graphic results. And the research work provides a theoretical basis for on-line stress monitoring and life assessment.

Energy Production in Solar Collectors in a University Building Used to Improve the Internal Thermal Conditions in Winter Conditions

In this numerical study the energy production in solar collectors in a University building used to improve the internal thermal conditions is made. Passive and active solutions, using external solar collector and internal thermo-convectors, are used. The numerical simulation, in transient conditions, is done for a winter typical day with clean sky. This numerical study was carried out using a software that simulates the Building Dynamic Response with complex topology in transient conditions. The software evaluates the human thermal comfort and indoor air quality levels that the occupants are subjected, Heated Ventilation and Air Conditioned energy consumption, indoor thermal variables and other parameters. The university building has 107 compartments and is located in a Mediterranean-type environment. External solar water collectors, placed above the building’s roof, and internal thermo-convectors of water/air type, using mixing ventilation, are used as passive and active strategies, respectively. The thermal comfort level, using the Predicted Mean Vote index, and the indoor air quality, using the carbon dioxide concentration, are evaluated. The results show that in winter conditions the solar collectors improve the thermal comfort conditions of the occupants. The indoor air quality, in all ventilated spaces, is also guaranteed.

Thermal analysis of a 1-kW hydrogen-fueled solid oxide fuel cell stack by three-dimensional numerical simulation

This study aims at elucidating the thermal characteristics and heat transfer mechanism of a commercial-scale, planar solid oxide fuel cell (SOFC) stack. The thermal management of a SOFC stack is key for its stable operation and market deployment. It is necessary to understand the internal thermal conditions and heat transfer pathways for satisfying such needs. In this regard, this study conducts three-dimensional numerical simulation accounting for an actual 1-kW stack geometry and its operating conditions. The thermal-flow conditions of the stack composed of 30 unit-cells are spatially resolved. Results show that temperature inside a stack changes in a way that it follows the air flow. As the air and fuel proceed to the top of the stack, the effect of the air flow is more prominent while showing a smaller temperature difference of unit-cells inside a repeating unit and a lower rate of its temperature increase. Given the temperature distribution, a large temperature gradient is imposed on unit-cells and sealants near the air inlet, especially in the lower repeating units. It is also shown that, in the direction of stack height, gaseous advection is a key pathway through which the heat released from a unit-cell is transferred, and conductive heat transfer through metallic interconnects contributes to the overall heat transfer rate at the top and bottom of the stack. As the gaseous advective cooling in the direction of stack height is reduced, the heat transfer rates towards the gas inlets and outlets within a repeating unit by interconnect conduction and gaseous advection, respectively, are also lowered, which is compensated by conductive heat transfer between repeating units. It can be inferred that controlling gas heating near the inlet manifold (especially, at the bottom of the stack), advection through the stack, and metallic conduction between repeating units may change the key heat transfer pathways and internal thermal conditions.

Development of a natural ventilation windcatcher with passive heat recovery wheel for mild-cold climates: CFD and experimental analysis

Abstract User demand for increased internal thermal comfort conditions have resulted in rising energy costs for space-heating consumption. The present study aims to recover the thermal energy in ventilation exhaust air and transfer the energy to the incoming air, to be redistributed using natural ventilation windcatcher. A comprehensive review was carried out to explore heat recovery systems that can potentially be incorporated with natural ventilation wind catchers. A rotary heat recovery device suitable to be incorporated with a roof mounted multi directional windcatcher system was developed. Computational Fluid Dynamics (CFD) modelling and laboratory experimental tests were conducted to investigate the proposed system. In the first phase, a full-scale prototype of the passive rotary thermal wheel device was developed and tested in a crossflow channel to initially assess the concept and performance of the design. Two configurations of the passive heat recovery wheel were tested: 20 and 32 radial blades. The second phase focused on investigating the integration of heat recovery wheel into a windcatcher system. CFD modelling and scaled wind tunnel testing were conducted to assess the airflow and temperature distribution around the multi-directional windcatcher with a passive rotary wheel. The results showed that the addition of the heat recovery wheel rotating at 15 rpm reduced the indoor airflow speed between 14 and 30%, depending on the outdoor wind conditions. The system was able to provide the recommended fresh air rates when the outdoor wind speed was 1.5 m/s and higher. In addition to sufficient ventilation, the heat recovery system had a positive impact on the indoor air temperature, raising the temperature up to 3.7 °C depending on the indoor/outdoor conditions.

The hot summer-cold winter region in China: Challenges in the low carbon adaptation of residential slab buildings to enhance comfort

The UK-China research project Low carbon climate-responsive Heating and Cooling of Cities (LoHCool) investigates enhanced indoor summer comfort in the 9 Billion m2 of building stock of the challenging Hot Summer and Cold Winter (HSCW) zone of China. The HSCW region lies South of the Huai River-Qin Mountain line below which central heating and cooling are deemed 'not required'. If this central government direction is relaxed, a significant carbon penalty could arise if the existing building stock is sealed and air conditioned to Western standards. LoHCool investigates the alternative strategy of increasing the existing stock's resilience to climate through low energy, low technology adaptation. The approach is applied here to typical slab building forms in Hangzhou and Chongqing in the East and West of the HSCW zone. Internal thermal conditions are simulated using the dynamic thermal model EnergyPlus calibrated using field data. Insofar as ventilation is a critical component of the adaptation schemes proposed, the local wind environment of the case study buildings is simulated using an advanced large eddy simulation model, Fluidity. Out of these diagnostic analyses, adaptation schemes are configured, specified and modelled, and found to significantly increase comfort with viable payback periods although supplementary cooling will be required as the century advances.

Field experimental study on a novel beehive integrated with solar thermal/photovoltaic system

Bees not only produce honey but also provide the main pollination for most crops, while long maturation cycle, low yield of honey and even mass death of bees are observed in traditional hives due to the unfriendly internal thermal condition. In the present paper, a new beehive system integrated with solar thermal/PV system was introduced to optimize the internal thermal condition of the beehive and then to improve the yield and quality of honey. A local bee farm was selected to evaluate the operating performance of the solar beehive in a real natural environment. Comparative filed testing of the solar hive and traditional hive were carried out under different operating modes depending on the weather conditions all the year round. The variation of hive temperature, the quantity of honey collected, Baume degree and the amount of sugar feed consumption were measured and analyzed. The results showed that the air temperature in solar beehive was higher than that in traditional beehive in winter and transition seasons and lower in summer. The quantity of collected honey in the solar beehive was 15.8% more than that in the traditional beehive. The Baume degree indicated that honey can mature 2 days earlier in solar beehive. As to sugar feed consumption in winter, the corresponding quality in solar beehive was lower than that in traditional hive. These results indicated the feasibility of the conjunctive use of solar thermal/photovoltaic technology with the beehive that enlarges the solar energy applications.

“Mind reading” building operation behaviour

Modern buildings are operationally classified as fully naturally ventilated (free running, FR), fully mechanically ventilated and conditioned (air-conditioned, AC) or intermediary (mixed mode, MM). Each strategy implies (i) the selection of different internal comfort models and controls, e.g. adaptive thermal comfort + operable windows in FR and static thermal comfort (Predicted Mean Vote - PMV) + non-operable windows in AC, and (ii) different energy consumption and carbon emissions with FR being the least (zero) and AC being the most. In each instance, the choice of strategy is dictated by the designer with little choice for the occupants. Here we ask the question: what operational mode would occupants select, given complete freedom? We examine this question using real concurrent data from three offices of similar size and use. In each, occupants have complete freedom in adopting FR, AC or a series of intervening MM strategies. We use monitored data on window and air-conditioning operation combined with internal and external thermal conditions to create validated computer models for each office. We discover the true operational mode of each office by comparing the computer model against 23 different scenarios using Dynamic Time Warping for binary (window open/close, AC on/off) and Euclidean distance for continuous operative temperature time series. Strikingly, results demonstrate that while each office used divergent strategies across the seasons, the indoor conditions were very similar and attainable through NV alone. This suggests that while a purely NV strategy is likely to deliver indoor thermal comfort, understanding occupant motivation and educating them on the impact of AC operation is needed to minimise energy use.

Design, Instrumentation and Usage Protocols for Distributed In Situ Thermal Hot Spots Monitoring in Electric Coils using FBG Sensor Multiplexing.

Random wound coils are a key operational element of most electric apparatus in modern industrial systems, including low voltage electric machines. One of the major current bottlenecks in improved exploitation of electrical devices is the high sensitivity of their wound components to in-service thermal stress. The application of conventional thermal sensing methods (e.g., thermocouples, resistance temperature detectors) for thermal condition monitoring of current carrying random wound coils can impose considerable operational limitations due to sensor size, EMI sensitivity and the existence of electrically conductive material in their construction. Another substantial limitation exists in distributed sensing applications and is caused by what is often a considerable length and volume of conventional sensor wiring leads. This paper reports the design of a fiber optic FBGsensing systemintended for enabling real-time distributed internal thermalcondition monitoring within random wound coils. The procedure of random wound coil instrumentation with the FBG sensing system is reported in a case study on an IEEE standard wound coil representative of those utilized in electrical machines. The reported work also presents and discusses important practical and technical aspects of FBG sensing system implementation and application, including the FBG array geometry design, sensing head and fiber packaging, the sensor array installation and calibration procedure and the use of a commercial interrogation system for obtaining thermal measurements. Finally, the in situ multiplexed FBG sensing system thermal monitoring performance is demonstrated in representative static and dynamic thermal conditions.