Indoor Temperature Conditions Research Articles

Comparative performance analysis of the artificial-intelligence-based thermal control algorithms for the double-skin building

This study aimed at developing artificial-intelligence-(AI)-theory-based optimal control algorithms for improving the indoor temperature conditions and heating energy efficiency of the double-skin buildings. For this, one conventional rule-based and four AI-based algorithms were developed, including artificial neural network (ANN), fuzzy logic (FL), and adaptive neuro fuzzy inference systems (ANFIS), for operating the surface openings of the double skin and the heating system. A numerical computer simulation method incorporating the matrix laboratory (MATLAB) and the transient systems simulation (TRNSYS) software was used for the comparative performance tests. The analysis results revealed that advanced thermal-environment comfort and stability can be provided by the AI-based algorithms. In particular, the FL and ANFIS algorithms were superior to the ANN algorithm in terms of providing better thermal conditions. The ANN-based algorithm, however, proved its potential to be the most energy-efficient and stable strategy among the four AI-based algorithms. It can be concluded that the optimal algorithm can be differently determined according to the major focus of the strategy. If comfortable thermal condition is the principal interest, then the FL or ANFIS algorithm could be the proper solution, and if energy saving for space heating and system operation stability is the main concerns, then the ANN-based algorithm may be applicable.

Performance assessment of thermal simulation approaches of wine storage buildings based on experimental calibration

Wine storage building should be designed to maintain specific indoor temperature conditions to ensure wine preservation. With this purpose, the goal of this study is the identification of an effective and efficient modeling approach suitable for common typologies of wine storage buildings. The specific aim is the assessment of the reliability and precision of different solutions for the discretization in thermal zones of the internal volume through horizontal “airwalls”, based on the comparison between digital simulation outputs with real recorded thermal data. Two different modeling approaches are analyzed through EnergyPlus thermal simulation software, by considering internal space consisting of one or two thermal zones. Simulation results are compared with data monitored for three years over a significant study case, and undergo a validation and acceptability procedure. The method proved to be a valid tool to assess results reliability in aboveground building modeling. The correctness of the use of “airwall” as horizontal partition was also verified. Results could help designers to optimize the building energy modeling.

Integrated control of the cooling system and surface openings using the artificial neural networks

This study aimed at suggesting an indoor temperature control method that can provide a comfortable thermal environment through the integrated control of the cooling system and the surface openings. Four control logic were developed, employing different application levels of rules and artificial neural network models. Rule-based control methods represented the conventional approach while ANN-based methods were applied for the predictive and adaptive controls. Comparative performance tests for the conventional- and ANN-based methods were numerically conducted for the double-skin-facade building, using the MATLAB (Matrix Laboratory) and TRNSYS (Transient Systems Simulation) software, after proving the validity by comparing the simulation and field measurement results.Analysis revealed that the ANN-based controls of the cooling system and surface openings improved the indoor temperature conditions with increased comfortable temperature periods and decreased standard deviation of the indoor temperature from the center of the comfortable range. In addition, the proposed ANN-based logic effectively reduced the number of operating condition changes of the cooling system and surface openings, which can prevent system failure. The ANN-based logic, however, did not show superiority in energy efficiency over the conventional logic. Instead, they have increased the amount of heat removal by the cooling system. From the analysis, it can be concluded that the ANN-based temperature control logic was able to keep the indoor temperature more comfortably and stably within the comfortable range due to its predictive and adaptive features.

Application of control logic for optimum indoor thermal environment in buildings with double skin envelope systems

This study proposes an effective thermal control method for thermally comfortable and energy-efficient environments in buildings with double skin envelopes. Four rule-based control logics and an artificial neural network (ANN)-based control logic were developed for the integrated control of openings and cooling systems in summer. Using numerical computer simulations, the performance of the proposed control logics was comparatively tested in terms of thermal performance and energy efficiency.Analysis results imply that the more detailed rules of thermal control logic were effective to maintain the indoor temperature conditions within comfortable ranges. The ANN-based predictive and adaptive control logic presented its potential as an advanced temperature control method with an increased temperature comfort period, decreased standard deviation of temperature from the center of the comfortable range, and decreased number and ratio of overshoots and undershoots out of the comfort range. The additional rules embedded for control logic or ANN applications yielded a more comfortable temperature environment in an integrated manner according to the properly designed operations of envelope openings and the cooling system. However, logics with additional rules and ANN models consumed more energy for space cooling. Therefore, the rule-based controls with advanced logics or an ANN model are required in case occupant comfort is a primary factor to be satisfied. In other cases, the simple rule-based logic is effectively applied.

Development of Rule-Based Logics for the Integrated Control of a Cooling Device and Openings of Double Skin Envelope Buildings

This study aims at suggesting an integrated rule-based logic for the optimal control of the heating device and openings of the double skin envelope buildings. Four different types of control logic were developed with different complexity of rules. Performance of the developed logic was numerically tested for a test module using the computer simulation method such as MATLAB (Matrix Laboratory) and TRNSYS (Transient Systems Simulation) in an incorporative manner. Analysis results revealed that as the rules were sub-divided for the proper thermal controls, the indoor temperature conditions were more comfortably maintained. However, the simplest rule-based logic consumed less energy for space cooling. Thus, if the thermal comfort is the major issue to be addressed, the sub-divided complex rule is beneficial to be applied. Or, the simple rule is more appropriate for the building energy efficiency.

Thermal adaptation and thermal environment in university classrooms and offices in Harbin

To study the influences of indoor and outdoor climate on thermal adaptation, a field study was conducted in classrooms and offices in winter and spring. The thermal environment parameters in the classrooms and offices were tested during the survey, while the subjects were interviewed on their thermal responses. The results showed that human thermal sensations were related to both indoor and outdoor climates. The neutral temperatures were not the same under different indoor temperature conditions in winter. The indoor microclimates had influences on human adaptability; the thermal neutral temperature was close to the indoor mean air temperature in thermal comfort environments. However, people felt hot when the indoor temperature was high and beyond the comfort zone in winter. Because the winter is long and outdoor temperature is low in Harbin, people have adapted to the cold environment. The indoor temperature should be kept at the lower limit of the comfort range in winter to keep human comfort and save energy. The neutral temperatures were different in winter and spring which proved that the outdoor climate influenced human adaptation. The indoor temperature in winter is suggested lower than that in spring, which is a comfortable and energy efficient regulation strategy. According to the regulation strategy, about 9.6% energy for centralized heating system can be saved.

Preliminary performance tests on artificial neural network models for opening strategies of double skin envelopes in winter

Abstract This study aims to develop Artificial Neural Network (ANN) models to examine the thermal performance of double skin-enveloped buildings under different opening conditions. Performance tests of the ANN models, which were developed for integrated temperature control logics, were conducted for a space with a double skin envelope in a one-storey building during the winter. ANN models were embedded in the logic for predictive and adaptive controls in order to ensure comfortable, energy-efficient indoor temperature conditions. Four ANN models were developed to predict future indoor temperatures under different opening conditions of the internal and external envelopes. Their performances were preliminarily tested by comparing them with conventional non-ANN-based methods in terms of thermal control and energy efficiency. The comparative analysis revealed that the ANN models were properly organized to predict future indoor temperature conditions. Based on the prediction accuracy, the optimal opening conditions and heating system operations could be determined to guarantee advanced methods for effective thermal control and energy efficiency. Thus, ANN models are expected to be applied to the temperature control logic for double skin-enveloped buildings in order to improve their thermal control performance and energy efficiency.

Fluid Balance and Sodium Losses During Indoor Tennis Match Play

This study assessed fluid balance, sodium losses, and effort intensity during indoor tennis match play (17 ± 2 °C, 42% ± 9% relative humidity) over a mean match duration of 68.1 ± 12.8 min in 16 male tennis players. Ad libitum fluid intake was recorded throughout the match. Sweat loss from change in nude body mass; sweat electrolyte content from patches applied to the forearm, calf, and thigh, and back of each player; and electrolyte balance derived from sweat, urine, and daily food-intake analysis were measured. Effort intensity was assessed from on-court heart rate compared with data obtained during a maximal treadmill test. Sweat rate (M ± SD) was 1.1 ± 0.4 L/hr, and fluid-ingestion rate was 1.0 ± 0.6 L/hr (replacing 93% ± 47% of fluid lost), resulting in only a small mean loss in body mass of 0.15% ± 0.74%. Large interindividual variabilities in sweat rate (range 0.3-2.0 L/hr) and fluid intake (range 0.31-2.52 L/hr) were noted. Whole-body sweat sodium concentration was 38 ± 12 mmol/L, and total sodium losses during match play were 1.1 ± 0.4 g (range 0.5-1.8 g). Daily sodium intake was 2.8 ± 1.1 g. Indoor match play largely consisted of low-intensity exercise below ventilatory threshold (mean match heart rate was 138 ± 24 beats/min). This study shows that in moderate indoor temperature conditions players ingest sufficient fluid to replace sweat losses. However, the wide range in data obtained highlights the need for individualized fluid-replacement guidance.

Cost-effectiveness Analysis of Improved Indoor Temperature and Ventilation Conditions in School Buildings

This paper reports simulation results of the potential fiscal benefits from investment in improved indoor environmental quality in school buildings. Improving indoor environmental quality can result in substantial benefits due to improved academic performance, but it can also result in increased energy and heating, ventilation, and air-conditioning (HVAC) maintenance costs. The aim of this paper is to demonstrate the cost-effectiveness of additional indoor environmental control by HVAC and the associated benefit of improved academic performance in a limited-scale school building model. This study estimated the impact of an increased ventilation rate and an alteration of target room air temperature on energy costs and on academic performance. The annual benefit due to improved thermal conditions (room air temperature) was up to five times higher than the benefit of increased ventilation rate per person. Lifecycle cost analysis showed that the benefit (improved academic performance) resulting from better indoor temperature conditions was up to 20–40% against the increased costs (increased HVAC total cost) of a few thousand JPY per year [JPY/year/person].

Energy in New Zealand houses: comfort, physics and consumption

The Household Energy End-use Study (HEEP) quantified how, where, when, and why energy was used in New Zealand houses based on the monitoring of energy and end-uses in a national sample of 400 houses. Based on these data, space heating was found to average 34% of total household energy use. Three issues are highlighted in relation to space heating: firstly, the extent to which low indoor temperatures are associated with persistent under-heating; secondly, whether some space-heating sources tend to be associated with higher (or lower) winter indoor temperatures than others; and thirdly, what the drivers of under-heating might be. An overview of the HEEP research and its complex data set is provided. The range of winter indoor temperatures are then compared with international benchmarks and established healthy temperature ranges. Occupants’ perceptions of winter indoor temperature conditions are presented and explored in relation to heating patterns and household energy consumption. The impacts of this research have assisted in changing public policy, moving from a narrow focus on energy efficiency toward an integrated energy, environmental, and health policy for the building stock and future interventions. L'Etude sur l'Utilisation Finale de l'Energie par les Ménages (HEEP) a quantifié comment, où, quand et pourquoi il a été utilisé de l’énergie dans les maisons de Nouvelle-Zélande, en se basant sur un suivi de l’énergie et des utilisations finales dans un échantillon national de 400 maisons. Sur la base de ces données, il a été constaté que le chauffage des volumes s’élevait en moyenne à 34% de l'utilisation totale de l’énergie domestique. Trois problèmes sont mis en évidence par rapport au chauffage des volumes: premièrement, il s'agit de savoir dans quelle mesure des températures intérieures basses sont associées à une insuffisance de chauffage persistante; deuxièmement, il s'agit de savoir si certaines sources de chauffage des volumes ont, plus que d'autres, tendance à être associées à des températures hivernales intérieures plus élevées (ou plus basses); et troisièmement, il s'agit de savoir ce que pourraient être les facteurs causant cette insuffisance de chauffage. Un panorama de l’étude HEEP et de ses données complexes est fourni. Les plages relatives aux température hivernales intérieures sont ensuite comparées aux données de référence internationales et aux plages de température admises comme bonnes pour la santé. La manière dont les occupants perçoivent les conditions de température hivernales intérieures est présentée et examinée par rapport aux habitudes de chauffage et à la consommation d’énergie par les ménages. Les répercussions de ces recherches ont contribué à modifier les politiques publiques, en évoluant d'une approche étroite axée sur le rendement énergétique à une politique énergétique, environnementale et de santé intégrée concernant le parc bâti et les opérations futures. Mots clés: performances des bâtiments, parc bâti, température demandée, précarité énergétique, logement, comportement des habitants, utilisation de l’énergie par les ménages, chauffage des volumes, Nouvelle-Zélande

EFFECTS OF LOW TEMPERATURE AND PHOTOPERIOD ON REPRODUCTION IN THE FEMALE WILD GUINEA PIG (CAVIA APEREA)

Small mammals in the tropics and subtropics usually rely opportunistically on favorable environmental conditions for breeding rather than base their breeding decision on prediction from photoperiodic cues as most high-latitude species do. Species producing precocial young may be more likely to reproduce aseasonally than species with altricial young. For female wild guinea pigs (Cavia aperea) from Argentina (35°S) that produce extremely precocial young, these hypotheses would predict moderate responsiveness of female reproduction to photoperiod. These predictions were tested in a series of laboratory experiments. Guinea pigs reproduced aseasonally when kept under natural photoperiod and temperatures at Bielefeld (52°01′N, 8°32′E). When given short days (9L:15D) and long days (14L:10D) under indoor temperature conditions (20–23°C), no effect of photoperiod on female reproduction was noted. A shift from long day length (14L:10D) to short day length (9L:15D) did not stop reproduction. Increasing energy expenditure for thermoregulation at low temperature (5°C) under long-day (14L:10D) conditions also did not inhibit reproduction. Wild guinea pigs thus reproduce throughout the year without respect to photoperiod as long as food and temperature conditions allow reproduction.