An approach to optimised control of HVAC systems in indoor swimming pools

Indoor swimming pools are recognised as having a high level of energy consumption and present a great potential for energy saving. The energy is spent in several ways such as evaporation heat loss from the pool, high rates of ventilation required to guarantee the indoor air quality, and ambient temperatures with expressive values (typically 28?30°C) required to maintain conditions of comfort. This paper presents an approach to optimising control of heat ventilation and air conditioning systems that could be implemented in a building energy management system. It is easily adapted to any kind of pool and results in significant energy consumption reduction. The development and validation of the control model were carried out with a building thermal simulation software. The use of this control model in the case study building could reduce the energy efficiency index by 7.14 points (7.4% of total) which adds up to an energy cost saving of 15,609€ (7.5% of total).     

Energy recovery in municipal swimming pools

After a discussion of heat losses and energy costs in municipal heated swimming pools, an analysis in presented of the performance of all of such pools in Northern Ireland. It is demonstrated that performance is generally well below that expected by the designers and reasons are identified as to why this should be so. The causes for poor performance are found to arise variously through poor design, inappropriate equipment selection and installation and bad control and operating practice. Part of the value of this study lies in the fact that as all pools in the region were included, with no pre-selection, the findings can be expected to be fairly representative of such installations throughout the United Kingdom.     

Solar heating of open swimming pools

This communication presents a thermal model for the performance of an open swimming pool. It is seen from numerical calculations that the combination of a pool cover and solar collectors (with an area equal to 75 per cent of that of the pool) enables the swimming season to be extended in Delhi, India to forty-seven weeks as compared to the period of twenty-nine weeks for an open swimming pool.     

Thermal model of solar swimming pools

This communication presents an analysis of heat transfer processes in the solar heating of a swimming pool. The solar insolation and atmospheric air temperature are assumed to be periodic, and the heat and mass transfer from the surface of the pool are taken into account. Analytical models corresponding to two cases, namely bare surface and surface covered with PVC cover have been developed. Numerical results indicate a substantial improvement in pool heating by the placement of transparent PVC cover on the surface and are in close agreement with the Australian experimental results.     

The heat balance of urban swimming pools

The energy balance and the resulting water temperature of urban swimming pools has been simulated throughout the summer in Toronto, using standard and derived climatological data, and well known micrometeorological equations of turbulent transer and radiative exchange. For 16 different combinations of sheltering, shading, landscaping and use of solar blankets and solar pool heaters, the results show that the major energy loss from pools is by evaporation during the day and by long wave radiation by night, and these losses can be effectively cut and hence water temperature raised by decreasing the wind, or using solar blankets or solar pool heaters. In the summer climate of Toronto, the best of these methods could increase maximum pool temperature by 3 or 5 K and lengthen the comfortable swimming season from an average of 40 days to 70 or 80 days.     

Experience with solar systems for heating swimming pools in Germany

The results of the demonstration programme “Efficient Use of Energy in Swimming Pool Construction” has had a positive effect on the dissipation of solar systems for swimming pools. Infrared measurements show how a homogeneous flow can be achieved in the absorber field. The fact that solar systems are acceptable can be seen clearly in evidence that the behaviour of visitors to purely solar-heated pools with variable water temperature does not differ in principle from conventionally-heated pools with constant temperature. Economic considerations of the operation show that swimming pool solar systems are competitive with conventional heating systems.     

Solar energy utilization for heating of indoor swimming pool

A simple transient analytical approach has been adopted for developing an explicit expression for the water temperature of an indoor swimmingpool coupled to a panel of collectors. For qualitative assessment of the analytical results, computations have been made for the winter climatic conditions of Sri Nagar, India. The effects of several parameters, viz. inlet temperature, heat removal factors, collector, etc. on the performance of the proposed systems have been studied in detail. It is observed that (i) the proposed model agrees with the experimental results of the Australian passive solar swimming pool and (ii) the desired temperature for the indoor swimming pool can be achieved by the active method.     

Analytical evaluation of direct solar heating of swimming pools

An analytical model for the long term thermal performance of swimming pools is developed and shows that the solution for open pools is applicable to enclosed pools with appropriate modification of parameters. From this solution the seasonal heating load of swimming pools, open or closed, can be calculated analytically.     

Analysis of directly heated open and closed swimming pools

The possibility of using the greenhouse effect to heat a swimming pool during cold winter months is investigated. A periodic analysis is developed to study the thermal performance of such a swimming pool. Numerical calculations are performed to compare the performances of open and closed swimming pools of this type.     

Analysis of implementing phase change materials in open-air swimming pools

Open-air swimming pools in Mediterranean climate regions are heated by direct solar radiation with no auxiliary heating systems. In order to extend the swimming season or improve comfort conditions, solar collectors or pool coverings may be used. In this paper, another approach was followed through the use of phase change materials (PCM). Two methods of introducing the PCM were considered: (1) encapsulated in the sidewalls and bottom of the pool, and (2) use the PCM in an external heat exchanger. Heat is stored when water temperature is sufficiently high, while it is released when water temperature drops below comfort levels. A numerical model was built and validated for predicting the evolution of the water temperature, by taking into account meteorological data at three different locations in north-east of Spain. The simulations showed that using phase change materials provided some improvement of water conditions, especially when used in an external heat exchanger.     

Energy-conservation standards for buildings in China

The People's Republic of China has recently designed an energy-conservation building standard which would require that, by 1990, the energy efficiency of new buildings be improved by 60% over existing practices. Present energy-conservation practices in China suffer from a lack of fully developed technical solutions and institutional support infrastructure. Given the greater complexity of the Chinese economy under the new reforms, the commitment to improving the efficiency of household energy use requires a broader focus beyond the formulation of a standard. In order for the standard to be successful, China will need to devote resources that may be more effectively utilized in other sectors of the economy.     

Thermal analysis of five unglazed solar collector systems for the heating of outdoor swimming pools

We have analysed measurements from five outdoor swimming pools located in Switzerland and heated by unglazed solar collectors. The main contributions to the daily energy balance of the swimming pools are evaluated. They include the active and passive solar gains, as well as the heat losses related to radiation, evaporation, convection, and water renewal (in order of importance). Coherent results are obtained using multilinear regressions in order to determine the best fitting values of the empirical parameters involved in the thermal equations.     

Energy-conservation management in organizations

To investigate the effects on energy-conservation management in organizations over time, a longitudinal study was designed to monitor five organizations for five years. They represent different types of organizations managing their own buildings in Sweden. Facilitating organizational structures and managerial practices are identified, and practical implications of introducing and maintaining energy-conservation management in organizations are discussed in detail.     

Problems associated with mechanical refrigeration based heat recovery systems in municipal swimming pools

The design of refrigeration-based heat recovery systems for municipal swimming pools is discussed and the performance of all such pools in Northern Ireland is analysed. It is found that most systems are incorrectly designed and specified, that the operating conditions are usually sub-optimal and that the control systems are normally either inappropriate or non-existent. It is clear that heat-pump based swimming pool heat recovery systems are not understood by either the designers, the equipment suppliers, the installers or the operators.     

Thermal and economic evaluation of heat recovery measures for indoor ice rinks

A comparative study of three ventilation systems supplying air to a typical Canadian indoor ice rink illustrates the power, energy and operating cost savings which can be achieved by using the relatively warm air from the air cooled condensers of the refrigeration system. The direct use of this warm air for ventilation results in a reduction of energy consumption during the winter amounting to 24.2% of the yearly consumption of the heating system. On the other hand, the use of a heat exchanger to heat the ventilation air results in energy consumption reductions throughout the year. Depending on the size of the heat exchanger these gains can be as high as 60.8% of the heating energy consumption by the existing system. Based on actual prices of electricity and the heat exchanger it is established that the cost savings over the life of the equipment are at least three times higher than the cost of the heat exchanger.     

基于三集一体热泵的某室内恒温泳池全年能耗分析

利用Dest软件计算某恒温游泳池全年动态空调负荷,并模拟三集一体热泵全年空气处理过程及运行能耗,通过与传统方案进行比较,阐明三集一体热泵在室内恒温游泳池应用的节能性、经济性。     

空气分级燃烧技术在电站锅炉节能减排上的应用

燃煤电站锅炉日趋成为NOx最大的污染源,NOx危害大,是当今社会严格控制的对象。降低飞灰含碳量是电站锅炉节能最主要的途径。通过空气分级优化燃烧技术可以很好的解决这两方面的问题。本文从一台锅炉的改造实例说明了空气分级燃烧技术对电站锅炉节能减排的作用。     

调速水泵的节能作用

在定速水泵和变速泵调节性能和节能效益对比分析的基础上,明确供热系统中使用定速水泵的不足,提出在热力系统中使用变速泵的必要性和优越性,通过实例进一步阐述使用调速水泵具有节能作用,同进能使管网处于稳定、高效的运行状态.