Investigation on the effectiveness of various methods of information dissemination aiming at a change of occupant behaviour related to thermal comfort and exergy consumption

These days the number of projects trying to urge a change in the occupant's behaviour towards a sustainable one is increasing. However, still less is known about the effect of such measures. This paper describes the findings of two investigations, a field measurement and an Internet-based survey, both including the dissemination of information about strategies for a high level of comfort without much energy usage. The focus was on the ability to quantify the effect of such measures on the heating and cooling behaviour. As a result, those who participated in a workshop were more likely to change their behaviour than those who received an information brochure only; whether this was due to the method employed or the type of participants could not be ascertained. However, the workshop participants reduced their cooling device usage by up to 16%. The concept of exergy was used to show how this reduction affects the exergy consumption of the cooling device, because it enables us to consider the qualitative aspect of energy as a quantity to be calculated. This showed that the exergy consumed by the workshop group was reduced by up to 20% comparing their behaviour before and after the information dissemination.     

Analysis on exergy consumption patterns for space heating in Slovenian buildings

Problem of high energy use for heating in Slovenian buildings is analyzed with exergy and energy analysis. Results of both are compared and discussed. Three cases of exterior building walls are located in three climatic zones in winter conditions. Results of energy analyses show that the highest heating energy demand appears in the case with less thermal insulation, especially in colder climate. If the comparison is made only on the energy supply and exergy supply, the results of exergy analysis are the same as those of energy analysis. The main difference appears, if the whole chain of supply and demand is taken into consideration. Exergy calculations enable us to analyze how much exergy is consumed in which part, from boiler to building envelope. They also reveal how much energy is supplied for the purpose of heating. Results show that insulation has much bigger effect than effect of boiler efficiency. However, the most effective solution is to improve building envelope together with boiler efficiency. Better thermal insulation also makes an important contribution to the improvement of thermal comfort conditions. It causes higher surface temperatures resulting in a larger warm radiant exergy emission rate and consequently better thermal comfort.     

Exergy-entropy process of passive solar heating and global environmental systems

The mechanism of a passive solar heating system and its relation to the mechanism of the global environmental system are discussed using the concepts of entropy and exergy. The reason that we use both of these concepts is to make it clearer how the systems work and hence why the passive solar heating system is called environmentally friendly. The mechanism of the systems is described as a process in which exergy is supplied, its portion consumed, and the resultant generated entropy is finally given off. We call this process “exergy-entropy process”. A numerical example of the exergy-entropy process of the passive solar heating system and the global environmental system revealed the following. Generated entropy within the passive solar heated room is discarded into the outdoor environment through glass windows and concrete floors. The global environmental system has a mechanism that disposes of all the generated entropy resulting from the solar exergy consumption on the Earth's surface into the universe. Passive solar heating systems therefore fit inside the global environmental system, on which they impose almost no burden.     

A relation between calculated human body exergy consumption rate and subjectively assessed thermal sensation

Application of the exergy concept to research on the built environment is a relatively new approach. It helps to optimize climate conditioning systems so that they meet the requirements of sustainable building design. As the building should provide a healthy and comfortable environment for its occupants, it is reasonable to consider both the exergy flows in building and those within the human body.Until now, no data have been available on the relation between human-body exergy consumption rates and subjectively assessed thermal sensation. The objective of the present work was to relate thermal sensation data, from earlier thermal comfort studies, to calculated human-body exergy consumption rates.The results show that the minimum human body exergy consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to the slightly cool side of thermal sensation.Generally, the relationship between air temperature and the exergy consumption rate, as a first approximation, shows an increasing trend. Taking account of both convective and radiative heat exchange between the human body and the surrounding environment by using the calculated operative temperature, exergy consumption rates increase as the operative temperature increases above 24 °C or decreases below 22 °C. With the data available so far, a second-order polynomial relationship between thermal sensation and the exergy consumption rate was established.     

Challenging the assumptions for thermal sensation scales

Scales are widely used to assess the personal experience of thermal conditions in built environments. Most commonly, thermal sensation is assessed, mainly to determine whether a particular thermal condition is comfortable for individuals. A seven-point thermal sensation scale has been used extensively, which is suitable for describing a one-dimensional relationship between physical parameters of indoor environments and subjective thermal sensation. However, human thermal comfort is not merely a physiological but also a psychological phenomenon. Thus, it should be investigated how scales for its assessment could benefit from a multidimensional conceptualization. The common assumptions related to the usage of thermal sensation scales are challenged, empirically supported by two analyses. These analyses show that the relationship between temperature and subjective thermal sensation is non-linear and depends on the type of scale used. Moreover, the results signify that most people do not perceive the categories of the thermal sensation scale as equidistant and that the range of sensations regarded as ‘comfortable’ varies largely. Therefore, challenges known from experimental psychology (describing the complex relationships between physical parameters, subjective perceptions and measurement-related issues) need to be addressed by the field of thermal comfort and new approaches developed.     

Exergetic view and thinking—for the development of environment‐conscious technologies

This article introduces the concept of ‘exergy’, which is a thermodynamic quantity, to show what resource is, and what consumption is. Exergy is the ability of energy and matter to disperse into their environmental space. The first part of this article briefly describes the essence of the exergy concept, and the second part describes a simple example of exergy calculation with respect to electric lighting and thereby reviews the importance of daylighting as one of the environment‐conscious technologies. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Adaptive temperature limits for air-conditioned museums in temperate climates

Indoor temperature (T) and relative humidity (RH) are important for collection preservation and thermal comfort in museums. In the 20th century, the notion evolved that T and RH need to be stringently controlled, often resulting in excessive energy consumption. However, recent studies have shown that controlled fluctuations are permissible, enabling improved energy efficiency. Consequently, the thermal comfort requirements are increasingly important to determine temperature limits, but knowledge is limited. Therefore, a thermal comfort survey study and indoor measurements were conducted at Hermitage Amsterdam museum in Amsterdam, the Netherlands for one year, including: (1) monitoring of existing conditions (T?=?21°C, RH?=?50%); and (2) an intervention in which T is controlled based on an adaptive comfort approach (T?=?19.5–24°C, RH?=?50%). The results show that the thermal comfort of the existing conditions is far from optimum; visitors feel too cool in summer and slightly too warm in winter. The adaptive temperature limits were developed to improve thermal comfort significantly without endangering the collection, thereby saving energy. Furthermore, facilitating visitors to adapt their clothing may contribute to enlarging the temperature bandwidth and improve (individual) thermal comfort.     

Energy and material use in the production of insulating glass windows

Waste heat, waste material, and waste water are estimated for the production of glass sheets and aluminum frames for architectural window systems. The purpose is to compare the wasted energy and matter in the production process and the heat loss through the window systems. Raw materials, fossil fuels, and fresh water are inputs, while waste heat, waste material, and waste water in addition to the products are outputs. Waste heat of 16.9 MJ versus 502.5 MJ, waste materials of 0.7 kg versus 5.4 kg, and waste water of 0.05 m³ versus 0.37 m³ are given off in the production of a glass sheet of 1 kg versus an aluminum frame of 1 kg. A comparison of a single glazed window and a double glazed window was made in terms of the waste heat at the production stage and the heat loss through the windows. It was found that the sum of the waste heat and the heat loss in the case of a double glazed window becomes smaller than in the case of a single glazed window within the first winter season in Tokyo.     

Comparison of theoretical and statistical models of air-conditioning-unit usage behaviour in a residential setting under Japanese climatic conditions

Occupant behaviour and its relation to energy use within the built environment have become more important in recent years. This paper first describes three statistical models based on a field survey and measurement for summer and winter respectively, which can be used to predict the percentage of air-conditioning-units used during night-time with a realistic assumption of human behaviour. The first statistical models are the results of a common approach to connect the occupant behaviour with the mean outdoor air temperature through the use of logistic regression. The present investigation extends these models to one including further external factors such as the mean outdoor air temperature the night before. The final models also include the preference and background of the individual subject. The statistical models are then compared to a theoretical model of occupant behaviour based on a comprehensive literature review. In conclusion, mean outdoor air temperature of the foregoing night(s) had a major impact on occupant behaviour during summertime, but a minor one in wintertime. The impact of the individual factors had the same magnitude as the external factors in summer, but an eight times higher impact in winter. Detailed research on the occupant behaviour is proposed to clarify further aspects of the theoretical model.     

Exergy concept and its application to the built environment

This paper discusses how a built environmental control system such as space heating and cooling can be described by the concept of “exergy”, which quantifies what is consumed by any working systems from man-made systems such as heat engines or buildings to biological systems including human body. The reason for the intensive and extensive use of exergy concept is to deepen our understanding of the built environment and thereby to develop a variety of low-exergy systems for future buildings. First, the essence of exergy balance equations is reviewed and then some results obtained from the recent exergy research were presented. The important findings described in this paper are as follows: (1) a volume of indoor air contains both of “warm” or “cool” exergy and of “wet” or “dry” exergy, whose values are comparable to each other especially for a hot and humid summer condition; (2) an ordinary air-source heat pump is basically a device to separate exergy supplied by electricity into warm, cool and dry exergies by consuming more than 85% of the supplied exergy; (3) there is a set of a little higher mean radiant temperature and a little lower air temperature, which provides with the lowest human body exergy consumption rate in winter season; (4) availability of cool radiant exergy of 20–40 mW/m² seems to play a key role for thermal comfort in a naturally-ventilated room in summer season; and (5) “cool” radiant exergy available from the sky in hot and humid regions amounts to 1000 mW/m², which is not necessarily small if compared to the values of cool radiant exergy to be supplied indoors.