Summertime overheating in dwellings in temperate climates

Summertime overheating in both new and existing dwellings is widespread and increasing, even in temperate climates. There is an urgent need to solve the problem. Flats (apartments) and small dwellings, especially those in cities, are particularly at risk. Elderly and vulnerable people are particularly affected. This briefing note presents current knowledge about this problem and what might be done about it. It is directed at planners, designers, policymakers as well as local authorities, housing associations and other organisations that manage stocks of dwellings. 'Key findings' • The research community and others have revealed the extent, severity and causes of summertime overheating in dwellings. • Flats, even in temperate climates, are particularly at risk of overheating. • Methods of construction and refurbishment and global warming are making the problem worse. • Overheating affects mortality and morbidity, with the elderly and vulnerable particularly affected. • Well-established passive heat-protection measures can, in most cases, prevent or remove the problem. • Examples of good design practice are being verified through monitoring and occupant experience surveys. • Professionals concerned with the design and refurbishment of dwellings must now focus on keeping them cool in summer as well as warm in winter

Design and operating concept for an innovative naturally ventilated library

Recent years have seen increased use of natural ventilation, daylighting, and cooling techniques in UK buildings. This paper describes the design and operating concept of a large, naturally ventilated and illuminated city centre library for Coventry University in the UK. The novel design concept includes four lightwells acting as ventilation inlets, each of which is fed with fresh air from a plenum below the ground floor. A central lightwell and perimeter stacks draw air across each floor plate and provide air extract routes. This strategy enables fresh air to reach the core of the building whilst keeping the external façade sealed for reasons of security and preventing urban noise and pollution. Computer simulation demonstrates that the building is likely to be well ventilated and thermally comfortable. The building and the analyses should increase the confidence of engineers and architects designing sustainable buildings

Retrofitting post-war office buildings: Interventions for energy efficiency, improved comfort, productivity and cost reduction

Within the UK non-domestic building stock, offices built between 1940 and 1980, are especially in need of retrofit, they can suffer from high energy consumption and thermal discomfort. Many post-war offices will still be in use throughout the first half of this century. This paper evaluates retrofit strategies for post-war office buildings accounting for the improved energy efficiency, thermal comfort and hence productivity, and reduction of capital and running costs. The aim of the paper is seeking optimal, generic retrofit strategies to provide guidance to building owners, occupiers and other decision makers. Dynamic thermal modelling is used to compare retrofit outcomes for existing building standards (PartL2B) and higher standards (Passivhaus retrofit: EnerPHit). The effects of location and orientation and both current and future UK weather conditions (2050) are considered. Multiple combinations of heating and cooling strategies and retrofit measures are assessed. The analysis methodology uses a sophisticated comfort, productivity and cost assessment. An Overall Building Thermal Discomfort (OBTD) index is introduced which enriches the current CIBSE overheating criterion 1 by including the number of occupants. Productivity improvements as a result of better comfort are included in cost calculations. Cost benefits are calculated both for buildings used by the owner (CBO) and for buildings let to a tenant (CBT). On cost and energy grounds, UK building regulation compliant retrofit is optimal provided that passive summertime overheating controls, such as night ventilation, blinds and/or overhangs, are installed. The EnerPHit standard retrofit provides resilience as the climate warms provided summer cooling is available, for example through mixed-mode ventilation

A novel shading analysis method for PV systems using sun path plots and high resolution performance data

This paper presents a technique for identifying and quantifying shading losses in PV systems. Five minute interval monitored data from domestic UK PV systems is used to assess the effects of trees and other shading objects on annual energy generation. Poor performance is identified from the relationship between in-plane irradiance and performance ratio. Shading events are identified by plotting the occurrences of poor performance on a ‘sun path plot’ of solar azimuth and elevation axes. Poor performance which concentrates about particular sun positions is identified as shading. Once identified, the energy loss due to shading is quantified

Determinants of high electrical energy demand in UK homes: socio-economic and dwelling characteristics

This paper provides an analysis of the socio-economic and dwelling factors contributing to high electrical energy demand in UK domestic buildings. The socio-economic, dwelling and electricity consumption data were collected during a large-scale, city-wide survey, carried out in Leicester, UK, in 2009–2010. Annual electrical energy demand was estimated for 315 dwellings and an odds ratio analysis used to identify the socio-economic and dwelling factors that led to high electricity consumption. The effects of a number of socio-economic and dwelling factors which have not previously been studied for the UK domestic sector are included. Thus, for the first time, presence of teenagers, having electric space heating as the primary form of heating, portable electric heating and electric water heating were identified as significant drivers of high electricity demand in UK homes. The employment status and education level of the Household Representative Person, the number of floors in a dwelling, presence of fixed electric heating, and the proportion of low-energy lighting were shown to have no effect on high electricity consumption in UK homes. Given the impetus to reduce electricity consumption and CO2 emissions from the domestic sector, these observations can help shape energy saving campaigns and future energy policy

Using historic cases to formulate appropriate sustainable building refurbishment strategy

Existing buildings are indispensable in a society and they will continue to exist until they reach the end of their service or economic life. While it is crucial to upkeep existing buildings, enhancing their sustainability is equally important as the energy performance of some older properties is usually less than satisfactory. Despite that, it is never easy for citizens to establish which is the most suitable sustainable refurbishment strategy for their properties. If historic cases can be captured and represented systematically, owners and occupants living in properties of similar types can review the outcomes of these cases to decide whether some sustainable building refurbishment solutions adopted by the others before are applicable to their property. In the paper, a prototype case-based reasoning model for sustainable building refurbishment is proposed. This paper demonstrates how to make use of the proposed model to retrieve and reuse previous cases to derive suitable sustainable building refurbishment strategies for existing buildings

An innovative low energy integrated health and social care building for a deprived community

The Braunstone Health and Social Care Centre will deliver an integrated service to one of the top ten deprived wards in the UK. Until now, the provision of health and social care was provided by separate services in discrete locations. This paper describes a project to house an integrated service model within a new sustainable building, exploiting passive solar principles and natural ventilation. The building has a deep plan punctuated by courtyards. Its section is configured to admit winter sun through controllable south facing rooflights. The building is of lightweight construction. Pre-cooling of ventilation supply air in summer is proposed via a belowfloor labyrinth. The risk of summertime overheating and the potential contribution of the pre-cooling is tested by computer simulation. The design, and in particular its energy aspects, is the product of widespread consultation with the public and the stakeholders. Conference Topic: Design Strategies, Case Studies, Low Energy Architectur

The socio-economic, dwelling and appliance related factors affecting electricity consumption in domestic buildings

This paper aims to investigate the socio-economic, dwelling and appliance related factors that have significant or non-significant effects on domestic electricity consumption. To achieve this aim, a comprehensive literature review of international research investigating these factors was undertaken. Although papers examining the factors affecting electricity demand are numerous, to the authors’ knowledge, a comprehensive analysis taking stock of all previous findings has not previously been undertaken. The review establishes that no less than 62 factors potentially have an effect on domestic electricity use. This includes 13 socio-economic factors, 12 dwelling factors and 37 appliance factors. Of the 62 factors, four of the socio-economic factors, seven of the dwelling factors, and nine of the appliance related factors were found to unambiguously have a significant positive effect on electricity use. This paper contributes to a better understanding of those factors that certainly affect electricity consumption and those for which effects are unclear and require further research. Understanding the effects of factors can support both the implementation of effective energy policy and aid prediction of future electricity consumption in the domestic sector

MEASURED INTERNAL TEMPERATURES IN UK HOMES -A TIME SERIES ANALYSIS AND MODELLING APPROACH

ABSTRACT This paper presents an analysis of internal air temperatures measured hourly in the living rooms of 10 domestic buildings in the city of Leicester, UK. Time series analysis is used to develop empirical models of room temperatures in rooms that are neither mechanically heated nor cooled, during the summertime period of July and August 2009. The models are used in predicting future temperatures based on past measured values. Such models can enable overheating risk alerts for homeowners and public authorities to be more accurately estimated and targeted

A comparison of quantitative methods for clinical imaging with hyperpolarized (13)C-pyruvate.

Dissolution dynamic nuclear polarization (DNP) enables the metabolism of hyperpolarized (13)C-labelled molecules, such as the conversion of [1-(13)C]pyruvate to [1-(13)C]lactate, to be dynamically and non-invasively imaged in tissue. Imaging of this exchange reaction in animal models has been shown to detect early treatment response and correlate with tumour grade. The first human DNP study has recently been completed, and, for widespread clinical translation, simple and reliable methods are necessary to accurately probe the reaction in patients. However, there is currently no consensus on the most appropriate method to quantify this exchange reaction. In this study, an in vitro system was used to compare several kinetic models, as well as simple model-free methods. Experiments were performed using a clinical hyperpolarizer, a human 3 T MR system, and spectroscopic imaging sequences. The quantitative methods were compared in vivo by using subcutaneous breast tumours in rats to examine the effect of pyruvate inflow. The two-way kinetic model was the most accurate method for characterizing the exchange reaction in vitro, and the incorporation of a Heaviside step inflow profile was best able to describe the in vivo data. The lactate time-to-peak and the lactate-to-pyruvate area under the curve ratio were simple model-free approaches that accurately represented the full reaction, with the time-to-peak method performing indistinguishably from the best kinetic model. Finally, extracting data from a single pixel was a robust and reliable surrogate of the whole region of interest. This work has identified appropriate quantitative methods for future work in the analysis of human hyperpolarized (13)C data.CJD is jointly funded by the National Institute for Health Research (NIHR), Cambridge Biomedical Research Centre and GlaxoSmithKline (GSK). Additional funding for this study was provided by Cancer Research UK (CRUK, C19212/A16628; C19212/A911376), The Wellcome Trust, Cambridge Experimental Cancer Medicine Centre, Cambridge Cancer Centre, the School of Clinical Medicine at the University of Cambridge and the CRUK and Engineering and Physical Sciences Research Council (EPSRC) Cancer Imaging Centre in Cambridge and Manchester.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/nbm.346