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The widespread adoption of low GWP alternative refrigerants across Europe is critical to achieving long-term carbon reduction emissions from the Refrigeration, Air Conditioning and Heat Pump (RACHP) sector. The RACHP sector has been identified as being responsible for significant greenhouse gas emissions through direct emission (leakage of high GWP refrigerants) and indirect emissions (energy use). The changes to EU's Fluorinated greenhouse gases (F-gas) regulation No 517/2014, which came to force since 1st January 2015, has enacted restrictions on the use of halocarbon refrigerants in certain applications with the intent of reducing the F-gas associated emissions in the EU region. There are currently inconsistent levels of knowledge and awareness of how alternative refrigerants can be sustainably procured and utilised. This paper provides an understanding of the needs for skills in some European countries, specifically covering the general overview of the “as installed“ RAC use, the current training provision, the potential use and status of alternative refrigerants and recommendations on procurement process. Furthermore, the paper discusses the availability of skills and existing training materials and template in specific European countries.

Boiling is an essential process for many industrial applications such as refrigeration, distillation, chemical processes. The efficiencies of these applications are dependent on effectiveness of the heat transfer processes. This study presents the experimental data analysis for pool boiling performance of 0.10~0.20% (wt%) of Multiwall Carbon Nanotubes (MWCNTs)/water nanofluid on smooth and straight, square and circular grooved surfaces. According to experimental results, the highest enhancement in boiling heat transfer coefficient is observed in configuration S4 consisting of 30mm deep circular groove inclined at 45° angle and 33% higher than the base fluid on the smooth surface. Based on this investigation, the paper indicates that the inclination of the circular groove has the potential to enhance significantly pool boiling heat transfer process. Furthermore, the paper justifies that the effectiveness enhancement analysis of the nanofluids under a range of concentrations and geometrical configurations of heat transfer surfaces is still essential and desirable.

Current electricity distribution systems allow prosumers to sell their surplus electricity back to the Distributed Network Operator (DNO). The export tariffs at which these sell-backs take place are considerably lower than the feed-in tariffs, offering little incentive to prosumers to sell their surplus energy. A peer-to-peer (P2P) electricity market where consumers and prosumers can interact by selling and buying energy between them at a premium rate that is lower than the standard feed-in tariffs but higher than the export tariffs is proposed. Such a system was modelled to process transactions every 20 s, and a simulation tool was created to obtain the total daily money flows between a consumer-prosumer pair. The inclusion of a Distributed Storage System (DSS) is also considered in the modelled system and simulation. The simulation results showed that the inclusion of a DSS is always beneficial for all parties in economic terms: consumers could save up to 6.4 % on the cost of their electricity while prosumers could save up to 49.1 %. A DSS could generate an income flow for the DNO of up to 6.9p/day per each consumer-prosumer pair.

This paper presents a feasibility study of the technical and economic viability of introducing combined heating and cooling networks in London, referred to collectively in this paper as “thermal networks”. The study begins with a review of the current and potential future demographic and energy trends for London. This is followed with detailed energy analysis of three different thermal network configurations to identify the most viable thermal network configuration for London. Future projection analysis was also carried based on a number of potential building mix scenarios. The study revealed that by using thermal network with heat recovery produced significant energy savings and subsequent carbon savings by upto 56%. The majority of the energy saving and equivalent CO⁠2 emission savings resulted from the reduction of the heating energy required to cater for the loads due the viability of heat recovery from the cooling network into the return of the heating network. The study also revealed that by utilising thermal networks, with central energy centre approximately 1831 tonnes of CO⁠2 equivalent could be saved per annum compared to traditional supply methods. With a minimum assumed system life of 25 years this equates to approximately 46,000 tonnes CO⁠2.

Single effect LiBr–H 2 O vapour absorption refrigeration (VAR) systems operate without using electromechanical energy and instead, they are powered using low-grade heat energy. The improved performance of these systems has always relatively depended on the continued use and improvement of conventional ancillary solution heat exchangers (SHXs). The inclusion of SHXs in VAR systems not only increase the risk of crystallisation but also the pressure drop in the solution lines and therefore necessitating high energy intensive electromechanical pumps for circulating the working fluids. Therefore, development of a novel VAR system incorporating a novel high efficiency regenerative heat exchanger with low maintenance costs and reduced risks of crystallisation is the subject of this paper. Specifically, this paper describes the modelling, design, manufacture and testing of a packed bed regenerative solution heat exchanger (R-SHX) for improved effectiveness of a novel VAR system.

VAR systems are heat powered refrigeration or air conditioning systems that can be operated without the use of mechanical or electrical energy. However, inefficiencies due to the high operating temperatures and/or additional electrical energy for operating mechanical pumps as well as high capital cost hinder the extensive use of these systems. The development of a novel VAR system incorporating a thermo-gravity pump and with reduced cost is the subject of this paper. An experimental apparatus consisting of a single stage LiBr–H 2 O VAR system is described. The apparatus incorporates two novel thermally activated valves for aiding circulation of system working fluids and a novel regenerative heat exchanger for improving the generator's and absorber's effectiveness. This paper describes the design and operation of a thermo-gravity pump also referred to as thermally activated pumping mechanism for circulating the refrigerant H 2 O (l) , water vapour H 2 O (v) , weak and strong LiBr–H 2 O (l) inside a novel VAR system.

The retail of food produces a large amount of carbon, both directly through embodied energy in the food and its packaging, and indirectly through energy use. Supermarkets are large consumers of energy in the UK, accounting for up to 5% of the UK’s total consumption. A large proportion of this energy, up to 50%, is used in refrigeration of food and much of this is used to cool open type display cabinets. However, work at Unilever Research Laboratory in the 1970s indicated that the input energy required for cooling open display refrigerated cabinets could be substantially reduced by applying low emissivity (i.e. high reflectance) materials in food packaging, causing the cabinet heat load and the temperatures of stored foods to be reduced. One drawback was that it was difficult to print on the surface of these materials without reducing their reflective properties. However, subsequent developments in packaging technology and the use of modern manufacturing processes have overcome the earlier disadvantages of these materials, permitting printing onto the external surfaces of low emissivity packaging, while still retaining its reflective properties. This paper presents an update of the Unilever study, in terms of the potential of modern, low emissivity food packaging materials for improving refrigeration system efficiency. The results of the new study indicate that some types of packaging will allow an increase in refrigerator operating temperature of up to 10 K, with no loss of refrigeration performance with respect to the food. This is expected to result in improved refrigeration system efficiency, with reductions of up to 30% in both energy consumption and carbon emissions and a likely significant increase in shelf life for stored foods. In addition, the embodied carbon for the packaging and the life cycle impact of its use, have been evaluated. Packaging having low embodied energy content has been identified, and it has been predicted that significant net savings in both carbon and energy are possible over the life cycle.

There has been an increased demand for use of cooling/refrigeration systems that make use of renewable energy sources and in particular solar thermal energy as a driving force due to its abundance and simplicity to harness. Solar powered cooling systems have been and continue to be utilized worldwide, for air conditioning in a range of applications and using different configurations, i.e., liquid and solid desiccant, absorption and adsorption, ejector and photovoltaic-compression cooling technologies. The specific benefits of solar-powered cooling have been highlighted through the review and comparison of the technologies in terms of solar coefficient of performance, capital cost, and life cycle cost.

The demand for natural resources has increased exponentially due to the consistent growth of the global population and urbanization. This has resulted to considerable environmental challenges that are potentially affecting the global sustainable development goals. Therefore, it is important to develop sustainable strategies to manage urban wastes as well as produce and utilize energy. Flammable gases being generated from the sewage systems can be a prospective renewable resource of energy. However, existing studies suggest that the potential of sewage gas utilization for energy production has not been explored effectively. This paper focuses on identifying key design elements of sewage systems in an Anaerobic Digester (AD) to optimize the process of conversion of human waste into energy source. The paper uses a kinetic model to describe the fermentation process and thus evaluating the effect of key parameters on biogas (specifically methane) gases production in an anaerobic digester environment.