On the energy consumption in residential buildings

On the energy consumption in residential buildings

13 Space heating and cooling the sensor of a room temperature controller depends on its position in the zone. Usually, the sensor is situated on a wal...

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13 Space heating and cooling the sensor of a room temperature controller depends on its position in the zone. Usually, the sensor is situated on a wall or near the HVAC system (e.g. radiator). The influence of the position of the sensor is analysed experimentally and by detailed simulation for different types of emitters. From this analysis, a detailed list of criteria for the development of zone models, adapted to controller tests, is obtained. The criteria are used to develop a new, dynamic model, able to distinguish between the temperatures at the centre and at different sensor positions. The developed model is then applied to closed-loop tests with a simulated controller for the case of a zone equipped with an electric convector. The results are presented for three controller types and are compared with the result using a well-mixed model.

03100800 Lithuanian energy efficiency project Kazakevi~ius, E. et al. Energy Policy, 2002, 30, (7), 621-627. The combined efforts of active homeowners, private businesses, the project management unit, state authorities and international financing institutions led to successful implementation of the Energy Efficiency Housing Pilot Project in Lithuania. This project was aimed at supporting private and public initiatives to reduce energy use in residential and public buildings. This article presents major results and lessons which can be useful for future design of similar undertakings in neighbouring Eastern European countries. Appropriate financing, workable legal framework, and extensive support network enabled more than 200 homeowners' associations and owners of individual houses as well as 12 municipalities to implement various packages of energy efficiency measures in their buildings. Assistance from the project donors enhanced awareness and active participation of private businesses by increasing the capacity of local energy consulting services and establishing a network of regional advisory centres providing support for homeowners on technical, legal, financial and managerial issues. Technical monitoring of the implemented residential projects has demonstrated that comprehensive packages of energy efficiency measures can potentially save up to 50% of heat. Social monitoring of the project participants indicated the need for wide-ranging assistance to households and key stakeholders to stimulate changes in perceptions regarding energy efficiency through experiences in undertaking energy efficiency improvements.

03/00801 Locating air-conditioners and furniture inside residential flats to obtain good thermal comfort Bojic, M. et al. Energy and Buildings, 2002, 34, (7), 745-751. Majority of residential apartments in Hong Kong may be equipped with up to three window-type air-conditioners that operate during 7 months of hot and humid weather. The units are placed in the living rooms and bedrooms. The positions of these units and furniture inside these small rooms are directed in some extent by the architectural design, however, residents have possibility to decide about their actual position. The occupants should locate their air-conditioner with respect to the room furniture to avoid the cold air re-circulation and draft, and to obtain good thermal comfort for residents. To accomplish this, flat manufacturers should give some recommendations to the occupants, and architects should include such concerns in their design. For three positions of an air-conditioner unit and one position of a bed and a cupboard in a typical Hong Kong residential bedroom, the air velocities, temperatures, and air diffusion performance index are determined by using the computational fluid dynamics (CFD) software FLOVENT. The cases with the maximum benefit and maximum consequences in terms of thermal comfort in the bedroom are identified.

03/00802 Measurements of air temperatures close to a lowvelocity diffuser in displacement ventilation using an infrared camera Cehlin, M. et al. Energy and Buildings, 2002, 34, (7), 687-698. The near zone of supply air diffusers is very critical for the indoor climate. Complaints of draft are often associated with low-velocity diffusers in displacement ventilation because the air is discharged directly into the occupied zone. Today, the knowledge of the near zone of these air supply diffusers is insufficient, causing an increased need for better measuring methods and representation of the occupied zone. A whole-field measuring technique has been developed by the authors for visualization of air temperatures and airflow patterns over a large cross-section. In this particular whole-field method, air temperatures are measured with an infrared camera and a measuring screen placed in the airflow. The technique is applicable to most laboratory and field test environments. It offers several advantages over traditional techniques; for example, it can record real-time images within large areas and capture transient events. The purpose of this study was to conduct a parameter and error analysis of the proposed whole-field measuring method applied to a flow from a low-velocity diffuser in displacement ventilation. A model of the energy balance, for a solid measuring screen, was used for analysing the influence of different parameters on the accuracy of the method. The analysis was performed with respect to the convective heat transfer coefficient, emissivity,

106 Fuel and Energy Abstracts March 2003

screen temperature and surrounding surface temperatures. Theoretically, the temperature difference between the screen and the ambient air was found to be 0.2-2.4°C for the specific delimitation in the investigation. However, after applying correction the maximum uncertainty of the predicted air temperature was found to vary between 0.62 and 0.98°C, due to uncertainties in estimating parameters used in the correction. The maximum uncertainty can be reduced to a great extent by estimating the convective heat transfer coefficient more accurately and using a screen with rather low emissivity.

03/00803 Measurements of whole-house standby power consumption in California homes Ross, J. P. and Meier, A. Energy, 2002, 27, (9), 861-868. The variation in standby power consumption in 10 California homes was investigated. Total standby power in the homes ranged from 14 to 169 W, with an average of 67 W. This corresponded to 5-26% of the homes' annual electricity use. The appliances with the largest standby losses were televisions, set-top boxes and printers. A short-term measurement of a home's utility meter can provide surprisingly good estimates of total standby power if certain precautions are taken. The large variation in the standby power of appliances providing the same service demonstrates that manufacturers are able to reduce standby losses without degrading performance. Replacing existing units with appliances using 1 W or less of standby power would reduce standby power use by 68%, achieving a 7% reduction in annual electricity consumption. At least 70% of new appliance purchases in these homes will have standby power consumption.


Method and apparatus for cooling of urban areas

Ishida, K. Jpn. Kokai Tokkyo Koho JP 2002 201,727 (CI. E04Bl/74), 19 Jul 2002, Appl. 2000/400,114, 28 Dec 2000. 6. (In Japanese) Hydrophilic layers or photocatalyst layers that have been hydrophilized by photoexcitation are formed on walls and roofs of buildings and water is supplied over the layers for cooling of the atmosphere and the building by evaporative latent heat. Buildings equipped with the said photocatalyst layers and a means for spray application of water are also claimed as having urban area cooling apparatus. The heat island effect in urban areas can be prevented.


New outdoor cooling design data for Turkey

Bulut, H. et al. Energy, 2002, 27, (10), 923-946. Outdoor design conditions are weather data for design purposes showing the characteristic features of the climate at a particular location. In this study, new outdoor design conditions for cooling were determined for 78 locations within Turkey according to the format recommended by the American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc. (ASHRAE). Dry-bulb temperature corresponding to 0.4, 1 and 2% annual cumulative frequency of occurrence and the mean coincident wet-bulb temperature, the mean and standard deviation of the annual maximum dry-bulb temperatures, and the mean daily ranges were obtained. In these calculations, the hourly data measured during at least 13 years were used. The current cooling design conditions used in the calculation of cooling load in Turkey were analysed based on their frequency levels. Comparison of the existing cooling design data with the data obtained in this study revealed that the current cooling design temperatures are generally stringent.

03/00806 On the energy consumption in residential buildings Mihalakakou, G. et al. Energy and Buildings, 2002, 34, (7), 727-736. A neural network approach is used in the present study for modelling and estimating the energy consumption time series for a residential building in Athens, using as inputs several climatic parameters. The hourly values of the energy consumption, for heating and cooling the building, are estimated for several years using feed forward backpropagation neural networks. Various neural network architectures are designed and trained for the output estimation, which is the building's energy consumption. The results are tested with extensive sets of nontraining measurements and it is found that they correspond well with the actual values. Furthermore, 'multi-lag' output predictions of ambient air temperature and total solar radiation are used as inputs to the neural network models for modelling and predicting the future values of energy consumption with sufficient accuracy.

03/00807 Personalized ventilation: evaluation of different air terminal devices Melikov, A. K. et al. Energy and Buildings, 2002, 34, (8), 829-836. Personalized ventilation (PV) aims to provide clean air to the breathing zone of occupants. Its performance depends to a large extent on the supply air terminal device (ATD). Five different ATDs were developed, tested and compared. A typical office workplace consisting of a desk with mounted ATDs was simulated in a climate chamber. A breathing thermal manikin was used to simulate a human being. Experiments at room air temperatures of 26 and 20°C and personalized