A passive cooling wind catcher with heat pipe technology: CFD, wind tunnel and field-test analysis

Wind catchers are natural ventilation systems based on the design of traditional architecture, intended to provide ventilation by manipulating pressure differentials around buildings induced by wind movement and temperature difference. Though the movement of air caused by the wind catcher will lead to a cooling sensation for occupants, the high air temperature in hot regions will result in little cooling to occupants. In order to maximise the properties of cooling by wind catchers, heat pipes were incorporated into the design. Computational Fluid Dynamics (CFD) was used to investigate the effect of the cooling devices on the performance of the wind catcher, highlighting the capabilities of the system to deliver the required fresh air rates and cool the ventilated space. Qualitative and quantitative wind tunnel measurements of the airflow through the wind catcher were compared with the CFD data and good correlation was observed. Preliminary field testing of the wind catcher was carried out to evaluate its thermal performance under real operating conditions. A cooling potential of up to 12 °C of supply air temperature was identified in this study

Analysis of vertical ground loop heat exchangers applied to buildings in the UK

The work presented here deals with the design and performance of ground-source heat pumps and ground-sink cooling systems using vertical borehole arrays for commercial applications in the UK. Heating and cooling energy demands for a range of building and HVAC plant options are obtained by thermal modelling applied to four HVAC plant options: space heating only; heating with chilled ceilings; fan coil units and constant volume all-air plant. Ground loop designs are conducted for each system option using an impulse-response method and the parameters extracted from this are used in 10-year simulations of plant response which have been carried out using HVACSIM+. The 10-year time horizon was used to assess any degradation in earth temperature over time. The results show that a substantial reduction in energy (and, hence, carbon) can be expected of up to and exceeding 50% when using ground source heat pumps for winter heating with direct cooling in summer in association with moderate temperature cooling systems such as chilled ceilings. A degradation of earth temperature was evident with systems utilising limited cooling or no cooling but this did not appear to influence heat pump performance greatly. Practical Applications: Design and performance data for use in vertical ground loop (borehole) heat exchanger arrays providing source heat for heat pumps as well as direct cooling for buildings are generated and reported in this paper. The data should be of help to design practitioners for the sizing of borehole arrays for both heating and cooling. Design and performance matching to a wide variety of HVAC combinations, building energy demand levels and two contrasting sets of earth thermal property data are included so that practitioners will be able to select results that suit a range of modern applications. Also included are results of 10-year energy simulations that demonstrate the required design and operating conditions needed to ensure that initial undisturbed earth conditions will not drift with time to an unacceptable extent. Comparisons are made with conventional heating and cooling methods so that estimates of carbon savings due to the use of ground-coupled heat pumps with (and without) direct cooling can be made

Climatic analysis of a passive cooling technology for the built environment in hot countries

The aim of this work was to determine the ventilation and cooling potential of a passive cooling windcatcher operating under hot climatic conditions by replicating the monthly wind velocity, wind direction, temperature and relative humidity (RH) observed in a hot-desert city. The city of Ras-Al-Khaimah (RAK), UAE was used as the location of the case-study and available climatic data was used as inlet boundary conditions for the numerical analysis. The study employed the CFD code FLUENT 14.5 with the standard k–ε model to conduct the steady-state RANS simulation. The windcatcher model was incorporated to a 3 × 3 × 3 m3 test room model, which was identical to the one used in the field test. Unlike most numerical simulation of windcatchers, the work will simulate wind flows found in sub-urban environment. The numerical model provided detailed analysis of the pressure, airflow and temperature distributions inside the windcatcher and test room model. Temperature and velocity profiles indicated an induced, cooler airflow inside the room; outside air was cooled from 38 °C to 26–28 °C, while the average induced airflow speed was 0.59 m/s (15% lower compared to a windcatcher w/out heat pipes). Field testing measurements were carried out in the Jazira Hamra area of RAK during the month of September. The test demonstrated the positive effect of the integration of heat pipes on the cooling performance but also highlighted several issues. The comparison between the measured and predicted supply temperatures were in good agreement, with an average error of 3.15%

Energy and economic analysis of Vacuum Insulation Panels (VIPs) used in non-domestic buildings

The potential savings in space heating energy from the installation of Fumed Silica (FS) and Glass Fibre (GF) Vacuum Insulation Panels (VIPs) were compared to conventional expanded polystyrene (EPS) insulation for three different non-domestic buildings situated in London (UK). A discounted payback period analysis was used to determine the time taken for the capital cost of installing the insulation to be recovered. VIP materials were ranked using cost and density indexes. The methodology of the Payback analysis carried out considered the time dependency of VIP thermal performance, fuel prices and rental income from buildings. These calculations show that VIP insulation reduced the annual space heating energy demand and carbon dioxide (CO2) emissions by approximately 10.2%, 41.3% and 26.7% for a six storey office building, a two floor retail unit building and a four storey office building respectively. FS VIPs had the shortest payback period among the insulation materials studied, ranging from 2.5 years to 17 years, depending upon the rental income of the building. For GF VIPs the calculated payback period was considerably longer and in the case of the typical 4 storey office building studied its cost could not be recovered over the life time of the building. For EPS insulation the calculated payback period was longer than its useful life time for all three buildings. FS VIPs were found to be economically viable for installation onto non-domestic buildings in high rental value locations assuming a lifespan of up to 60 years

Public toilets: The need for compulsory provision

There is no mandatory requirement for local authorities to provide public toilets. Yet, it is argued, they are a vital component in creating accessible, sustainable and comfortable cities for all. In this paper the reasons for compulsory standards are explained, and the underlying problems of current provision and regulation are investigated. The nature of a spatial toilet strategy in respect of the adequate distribution and location of public toilets is outlined. Changes in the regulatory and organisational aspects of public toilet provision are proposed that would result in a better standard of facilities for twenty-first century needs

The aluminium extrusion industry

Best practice programmeSIGLEGBUnited Kingdo

The Building Act 1984 The Building Regulations 2000: proposals for new safety requirements for electrical installation work in dwellings

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