Estimation of Cooling Energy Demand and Carbon Emissions from Urban Buildings using a Quasi-dynamic Model

Global warming and the urban heat island effect in large towns and cities demand new approaches to cooling buildings in an efficient and sustainable way. Modern refrigeration, air conditioning and heat pump (RACHP) systems can achieve a high coefficient of performance and low emissions, but refrigeration technology already accounts for around 15% of worldwide electricity use and up to 10% of all greenhouse gas emissions, so in the context of international agreements to reduce global greenhouse gas emissions by up to 80% RACHP systems alone cannot provide a sustainable cooling solution for cities. The purpose of the model described in this paper is to provide a simple and easy to use tool to estimate the impact of different heating and cooling technologies, alternative building design and operating parameters and future global warming, on the energy demands and carbon emissions of buildings. Existing software tools for analysis of buildings can provide high quality results for a given scenario, but the determination of an optimal solution demands multiple simulations, which can be time consuming and require post processing to interpret the results. The Excel based tool uses a quasi-dynamic energy balance model and reduced weather data set to generate rapid results, allowing the user to view the building’s temperature profile, energy demands and carbon emissions in near real time and to develop an optimum cooling strategy. Results are presented for a single building version of the tool. When fully developed, it will allow the user to model clusters of buildings in an urban environment

Simulation of the heat recovery use of R744 systems in a supermarket

This paper describes the outcomes a research project that investigate the improvement in the COP of an enhanced booster R744 refrigeration system that provided MT cooling for chilled food cabinets and LT cooling for cold room/frozen food cabinets by recovering the heat rejected and using it more for other building services applications in the supermarket. For instance, the heat reclaimed can be used for heating, HWS or to drive absorption chillers, either in whole or in part. To demonstrate the potential of the heat reclaimed within the supermarket and its impact on the store’s CO2e emissions, a feasibility study has been performed to examine the innovative system compared to of the existing conventional system which will cover the cooling demands of an existing supermarket. In order to achieve this, the data collected by a smart energy monitoring system will be used to examine the working of the novel system when covering the cooling demands of the store. The energy consumption of the novel system will be analyzed according to thermodynamic theory. Using an Excel model, the potential heat reclaimed will be mathematically investigated for best practice applications of heat recovery. The energy saved and CO2e emission reduction achieved in apply the novel system will be determined and analysed

HARNESSING DAYLIGHTING AND SOLAR GAINS AS SUSTAINABLE ARCHITECTURAL DESIGNMETHODSIN MIXED-USE DEVELOPMENTS IN LAGOS, NIGERIA.

Thebuilt environment contributes around 40% of the world’s total carbon footprint,resulting in high building energy costs and pollution, as well as detrimental effects on the environment through the use of engines. Energy consumption can be very high in buildings, especially in mixed-us facilities. This paper seeks to analyse and contribute to the existing knowledge on daylighting and solar gain measures, resulting to a sustainable method of achieving energy efficiency in buildings. The methodology adopted for this study involves the use of case studies of two nationalandone international buildings of mixed-use typology which were appraised by evaluatingand criticizing. Criticalanalyses of physical and daylighting measures of existing developments were evaluated, pointing out merits and demerits of existing strategies as adopted in the cases.Findings from this study evince thattheneed for office and residentialspaces despite the unavailability of land in Lagosresulted in the concept of mixed-use developments. Also, some daylighting and solar gainsstrategies have been adopted but not fully maximized in Nigeria, especially the use of light shelves to enhance day lighting. Thispaper recommends that the techniques to be used to enhancedaylightingand solar gains, materials and designs;theplacements and orientations,should be determinedright from conceptualization,through to the architecture process (design and construction)

Circular economy and behaviour change: Using persuasive communication to encourage pro-circular behaviours towards the purchase of remanufactured refrigeration equipment

Refrigerated Display Cabinets (RDCs) are used in the retail sector to display chilled and frozen food, and beverages. The manufacture of RDCs is typified by the extensive use of materials and energy, meaning that the development of a Circular Economy in this sector is particularly important. A number of behavioural barriers are preventing the development of the Circular Economy but an appropriate behaviour change intervention could help to overcome them. This paper investigates how effective the use of Persuasive Communication could be in influencing the Behavioural Attitudes, Product Perceptions and Behavioural Intentions towards the purchase of remanufactured RDCs. Participants in this study are engineers and academic experts of retail refrigeration equipment. The study was carried out in three consecutive stages. In the first stage participants completed a questionnaire, which assessed their Behavioural Attitudes, Product Perceptions and Behavioural Intentions. In the second stage participants were exposed to the intervention, which was the Persuasive Communication in the form of an audio-visual presentation. In the third stage participants completed a second questionnaire which assessed the impact of the intervention. The results show that the Persuasive Communication had a positive impact on the participants' Behavioural Attitudes, Product Perceptions and Behavioural Intentions towards the purchase of remanufactured RDCs. This paper demonstrates how effective this type of intervention could be, if developed further to create a target market and generate demand for remanufactured RDC

Cooling Effect of 3D Oscillating Heat Pipe with Nanofluid on Photovoltaic Panel in Hot Climates

Nowadays, there has been a growing trend toward using photovoltaic systems due to their high efficiency and cost-effectiveness; nevertheless, an inevitable side of solar panels is that their efficiency and life span experience a reduction when they are exposed to high intensity of solar irradiance and warm-up. In other words, when they are cooled, the electrical efficiency is promoted. Using oscillating heat pipes is a creative and practical approach to enhance PV efficiency. Furthermore, applying nanofluid as a working fluid can play an important role in maximizing panel productivity. The main objective of this investigation is to explore the cooling effect of a three-dimensional oscillating heat pipe on a photovoltaic panel, while graphene oxide nanofluid and distilled water are used as coolants. For this purpose, a novel three-dimensional oscillating heat pipe has been designed. The significant result from the study is that the cooling system was able to lower the temperature and improve the power output of the PV by 8.6 °C and 2.78 (W), respectively, in the warmest time of the day, when graphene oxide nanofluid was used as a coolant

Viability of Airborne Wind Energy in the United Kingdom

To meet the worldwide requirements of carbon emission reduction, the European Council has set the UK a 15% energy target to come from renewable energy by 2020. The biggest renewable energy sources in the UK are bioenergy, wind, solar and hydro. The UK is located in prime geography, considered to be the best in Europe, for harvesting and over the last three decades, the number of wind farms has increased greatly. However, the interaction of wind speed and structural strength have limited the height of platform-based wind turbines to a maximum height of around 100 m. Airborne Wind Energy (AWE) systems enable the extraction of more energy from the wind at elevated altitudes beyond 150 meters using a device termed a kite. A method is required to determine suitable locations for AWE system implementation. In this work, a regional feasibility study is conducted to establish an ideal suitable location to implement the AWE system. Extensive work has been carried out to assess the electricity costs and energy savings, area availability as well as regional airborne wind energy power densities at different regions within the UK. A standardised method has been developed to assess the viability of AWE in various geographical locations. It was found that Scotland was the most suitable location for the implementation of an AWE systems due to the high wind power density in this region and existing high costs of electricity thus greater potentials for energy cost savings. This is the pre-print version of an article printed in the Journal of Thermal Science and Engineering Applications, published by the American Society of Mechanical Engineers. The full published version is available online at: http://thermalscienceapplication.asmedigitalcollection.asme.org/journal.asp

Carbon Reduction and Energy Optimization Strategy for one NHS Trust

Energy managers at many National Health Service (NHS) hospitals are now under intense pressure to radically investigate and develop energy and carbon reduction strategies. Factors contributing to this pressure include new Government and NHS carbon reduction targets, reduced energy budgets, increase of energy demand and energy cost. The increase in energy demand in many NHS hospitals is also influenced by the age of the infrastructure, rapid demand and expansion along with increased use of energy intensive medical kits in certain specialist hospitals. This paper presents a detailed analysis of energy data spanning 6 years for The Royal Marsden NHS Foundation Trust. The analysis, together with a survey of existing systems forms the basis for profiling the hospital historical energy consumption trend and to determine the average “Business As Usual” growth rate for energy, and the resultant costs. Further investigation of short and long term energy saving measures was undertaken based on the analysis of the effects of previously implemented measures and the hospital energy profiles. New energy savings measures have also been identified using financial and carbon emission savings studies

Study of Energy and Cost Savings of Demand Controlled Fresh Air Systems

This paper presents findings from a study on the energy and cost savings of Demand Controlled Fresh (outdoor) air systems for existing office buildings. The study was based on technical analysis of data from an existing 11 storey office building located in London. The study proposed a retro-fit mechanical system and control solution to convert the existing constant volume fresh air system to a demand based system. The four key parts of the proposed system were the occupancy detection device, local ventilation zone branch control, central ventilation plant control and overall controls logic. The building and proposed control solutions were simulated. The results revealed up to 39% annual energy savings for the fresh air plant. This equates to 4% reduction of the overall building annual energy and an overall building annual energy cost saving of around 3%

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

Smart Cities – Thermal Networks

This paper presents a feasibility study of the technical and economic viability of introducing combined heating and cooling networks, referred to collectively in this paper as “thermal networks”. The steps used for this study include the identification of the most viable thermal network configuration, followed by analysis of a number of potential building mix scenarios and estimation of their respective potential impact on energy consumption, carbon emissions and economics. The final step was a discussion of the potential benefits and drawbacks associated with the implementation of the selected thermal network. This study revealed that by utilising thermal networks, with central energy centres, approximately 1831 tonnes of CO2 could be saved per annum compared to traditional supply methods. With a minimum assumed system life of 25 years this equates to approximately 46000 tonnes CO2. It has also been identified that, in conjunction with a marginal shift in policy to encourage an increase in service led economy, thermal networks can become technically and economically viable with around 40-year net present value payback periods and by introducing financial support from governments, such as 9 – 12 pence investment per kWh of cooling, the payback periods could be reduced to around 25 years