The potential for heat recovery from urban wastewater.

The pressing need of implementing climate change act and a commitment to increase renewable energy has led to the identification of number of secondary heat sources in UK (1). This paper focuses on heat recovery from urban sewage wastewater - a secondary heat source. The heat that is added by the consumer when it is heated, used and dumped in the sewer systems. The technique is not new and have been successfully implemented in many cities around the world with many others considering its deployment. In UK there is a growing interest to explore this new technology specially after the successful sewage heat recovery demonstration project at Borders College, Galashiels, Scotland - a joint venture between Scottish Water Horizons & SHARC Energy Systems (2). However, further experimental research is needed to build the evidence base, replicate and de-risk the concept elsewhere in the UK. The Home Energy 4 Tomorrow (HE4T) project at London South Bank University (LSBU) was created to address this evidence gap. The current paper is third in series of output on wastewater heat recovery in UK and is motivated by the need to introduce the research done to the industries where the data pertaining to sewage wastewater heat recovery is scarce and there is a lack of understanding of the flow behaviour of urban sewage. In this paper we present some measured data from a location in London, monthly variations in sewage wastewater temperature and the heat potential along with policy implications for UK heat strategy

Time-of-Use Tariff with Local Wind Generation

Renewable energy, such as wind power, is known to significantly reduce system costs and carbon emissions. However, traditional Time of Use (ToU) tariffs fail to account for local energy generation. To overcome this limitation, we propose a mechanism for calculating new ToU tariffs that incorporates Agile ToU and local energy resources, such as a wind farm. By partially supplying local consumption, wind energy can reduce electricity costs for consumers and encourage load shifting towards peak renewable energy production periods. We demonstrate the effectiveness of the proposed mechanism by testing it on a case study of a residential area in Wales, UK, where electricity would be partially supplied by a nearby wind farm with 5 turbines through a Power Purchase Agreement (PPA). The results show that the new tariff significantly reduces electricity bills

Turning national retrofit policies into local action: examples from the US BBNP and the Canadian eco-energy programs

Improving energy efficiency in existing dwellings is critical in efforts to address climate change. National level retrofit policies are useful for delivering large volumes of funding with a coordinated program brand. However, for countries such as the US and Canada, energy issues vary considerably nationwide and are therefore governed at the state or provincial level. Finding ways to calibrate national level policy objectives and structures for effective delivery at the local level is a critical policy priority, but is poorly understood by policymakers and underrepresented in academic research. This paper addresses this gap by analysing the US Better Buildings Neighborhood Program (2010-2013), and the Canadian Eco-Energy Retrofit Program (2009-2013). Both of these programs were created with a national level overarching structure and objectives, but were implemented in different ways at the state/provincial and local levels. The impact evaluations of each program found that they were broadly successful at the national level. This paper considers how each program targeted local action along three themes. 1) Housing stock factors including population, social, and demographic issues inherent to the spatial distribution and fundamentally unchangeable. 2) Program design factors consider issues such as leveraging local funding and resource pools. 3) Program delivery factors include implementation strategies for driving demand and workforce engagement. The results suggest that demographic factors are not predictive of overall program success (measured as total upgrades and/or energy savings). Effective program design and implementation can compensate for housing stock factors. A set of best practice principles are described for adapting national level program structures for effective local program delivery

Lessons for the UK Green Deal from the US BBNP

How can programme design and strategy drive the decision actually to undertake retrofit upgrades? The US Better Buildings Neighborhood Program (BBNP) and the UK Green Deal both represent ambitious efforts to drive domestic retrofit markets. These programmes are compared and the differences in their conversion rates explored in the context of marketing, outreach and workforce engagement strategies. The impact of financial incentives is also explored. This paper supports the consensus that the US BBNP was successful against most of its stated objectives. The UK Green Deal, while slow to start, was gaining momentum before it was effectively ended. Semi-structured interviews with programme organizers give evidence that the Green Deal would have benefited from a more active approach to marketing and outreach, specifically emphasizing the distinction between the two. Marketing generates interest, but local outreach through word of mouth and personal referrals is needed to drive upgrades. The Green Deal did not sufficiently engage the workforce through an ongoing communication strategy and should have better facilitated both technical and non-technical skills development. The interest rate of the Green Deal is shown to be but one factor influencing participation, and can be effectively balanced through programme design in other areas

Participation in domestic energy retrofit programmes: key spatio-temporal drivers

The Canadian government created the EcoENEGY Retrofit for Homes programme (2007–12) to improve residential energy efficiency and reduce emissions produced through energy use. The uptake of retrofits varied both spatially and temporally. This research examines spatio-temporal patterns of retrofit adoption to understand the drivers behind participation in the grant programme and assess how future grant-based programmes might improve the uptake of efficiency measures. Temporal analysis demonstrated continued growth of programme participation over its original period of availability, and this accelerated once the programme was extended for an additional year after its original closure date. However, some spatial correlations weakened, which may be attributable to changes in programme design during the extension period. Seasonal variation was also observed, with spikes in retrofit activity occurring in winter. A regression analysis for conversion rates in Ontario and British Columbia displayed significant positive correlations for high shelter costs (>30% of household income) and households occupied by usual residents (regular occupants). Population density, median property value (only in Ontario) and units that were recently occupied demonstrated negative correlations. Spatial variation at both the city and neighbourhood levels suggests a greater degree of programme customisation is required to ensure uniform building stock improvement

Enabling local rapid change solutions to the Climate Emergency

Three quarters of UK Local Authorities (LAs) have declared Climate Emergencies. Most include an ambition for carbon neutrality by 2030. Yet a lack of clarity on a national policy framework through to 2030 means that LAs now face the challenge of creating an enabling environment to respond to urgent Climate Emergency targets. This paper reviews the implications of the LA Climate Emergency Declarations for local policy making in respect of low carbon retrofit. It will focus on evidence from a council whose dedicated project team is creating and implementing 2030 Climate response strategies, as well as built environment practitioners who have expertise to deliver retrofit services. Using documentary evidence and expert testimony, this paper will explore the gaps in creating an enabling environment/policy roadmap to 2030, the role might local government play in delivering large scale domestic retrofit, and how to align the various stakeholder groups. The paper finds that despite the simplistic term ‘retrofit’, the domestic retrofit landscape is far from simple. It is not a homogenous entity, rather a complex, multi-layered and segmented eco-system. We propose reviewing this segmentation through the lens of ‘first-mover’ which would help clarify where efforts should be focused, and which measures could be taken to accelerate consumer engagement. The authors discover there is potential for Local Authorities to develop novel approaches to retrofit processes, by taking the role of ‘middle actor’, reshaping the customer journey and engaging a range of stakeholders to stimulate local economies and deliver on social and environmental goals. Open collaboration with third sector organisations can provide access to research, resources, and networks to help deploy rapid change solutions

The Theoretical versus Practical Potential of Existing and Emerging Wastewater Heat Recovery Technologies

The UK heating sector must be completely decarbonized by 2050. The deployment of low carbon heat is thus an urgent policy and research priority. Multi-vector energy systems will be critical in this effort, and there is considerable potential for efficiency gains through better coordination between heat and water utilities. Urban wastewater contains a large amount of thermal energy that can be recovered and utilized to improve the performance of heat pumps. This is a potentially economical means of replacing fossil fuels with low carbon heat that reduces greenhouse gas emissions. According to a 2013 study, London needed 66 TWh/year for its heating needs in 2010, and there is 50 TWh/year available from existing secondary heat sources in and around London. Of this, an estimated 232 GWh/year could come from sewer mining. In last decade, many cities around the world have successfully implemented wastewater thermal energy recovery. In this paper we will explore the existing wastewater heat recovery systems operating around the world, their performance and viabilit

Review of Intelligent Control Systems for Natural Ventilation as Passive Cooling Strategy for UK Buildings and Similar Climatic Conditions

Natural ventilation is gaining more attention from architects and engineers as an alternative way of cooling and ventilating indoor spaces. Based on building types, it could save between 13 and 40% of the building cooling energy use. However, this needs to be implemented and operated with a well-designed and integrated control system to avoid triggering discomfort for occupants. This paper seeks to review, discuss, and contribute to existing knowledge on the application of control systems and optimisation theories of naturally ventilated buildings to produce the best performance. The study finally presents an outstanding theoretical context and practical implementation for researchers seeking to explore the use of intelligent controls for optimal output in the pursuit to help solve intricate control problems in the building industry and suggests advanced control systems such as fuzzy logic control as an effective control strategy for an integrated control of ventilation, heating and cooling systems

Comparison of Real-world Data with Simulated Results to Enhance Building Thermal Retention when using Shading Devices

Managing thermal loss is a key topic that needs further investigation as it has a direct link to reducing the energy load in buildings. One of these thermal loss management methods can be the use of shading devices. Dynamic thermal models normally used at the early stages of the building design can play an important role in the decisionmaking process regarding the use of shading devices. This paper presents the results of a real-world study assessing the potential of using a sealed cellular blind as a passive energy conservation method, where the real-world results are compared with the simulated results generated with EDSL Tas. During the real-world study, a positive impact of having blinds was seen whereby the window surface temperature increased and office heating energy consumption was lowered. EDSL Tas was able to predict a similar trend of results for the window surface temperature but not for the energy consumption. This was mainly due to the inability of the software in demonstrating the effect of infiltration of the blind