Caterina Brandoni

Assessment of the impact of local energy policies in reducing greenhouse gas emissions.

The present work investigates the potential energy savings coming from a careful and detailed local energy policy. The paper analyzes and assesses from technical, economic and environmental viewpoints different initiatives in the energy sector aimed at increasing energy efficiency in end-uses and reducing overall carbon emissions. The results are based on energy planning for five Italian urban areas sized at about fifty thousand inhabitants. The analysis has been developed with the aim of reaching generally applicable criteria suitable for evaluating the local energy policy contribution to the greenhouse gas (GHG) emissions reduction. Several initiatives for the private and public sectors have been considered, such as: (i) the introduction of combined heat and power generation based on useful thermal demand, suitable for the industry and service sectors (swimming pools, large distribution organizations); (ii) generation of electricity from renewables (solar energy, biomass); (iii) thermal insulation of private and public buildings, such as schools; (iv) introduction of micro-combined heat and power generation in the residential sector. For each solution the primary energy reduction and the consequent reduction in GHG emissions have been evaluated and a feasibility analysis has been developed in order to assess the profitability of the investment. Great attention has been paid to the public sector, which has an important role in providing leadership and driving changes in other sectors; furthermore, a rational use of energy combined with the exploitation of country-based incentives is able to reduce the public administrative expenditure. The results show that local energy policy can give an important contribution to gas emission reduction targets, and underline the fundamental role of public sector initiatives.

PERFORMANCE ANALYSIS OF COGENERATIVE AND TRIGENERATIVE PLANT WITH MICROGAS-TURBINE

The paper reports on the performance analysis of cogenerative and trigenerative plants based on Micro Gas Turbines. The core of the system is a natural-gas-fuelled Turbec T100 operating on a regenerated open-air cycle. A code specifically developed by the authors to simulate the micro gas turbine in cogeneration plants, and already checked against experimental data, has been upgraded to simulate the units behavior when facing also a cooling demand (trigenerative case). For this purpose the model of a water-LiBr single-effect absorption chiller driven by hot water has been used. The analysis cover all the units application range and represent a start for its economic evaluation.

Vapour Compression Heat Pumps and District Thermal Energy Networks for Efficient Building Heating and Cooling

Abstract Purpose Currently heating and cooling in buildings is responsible for over 30% of the primary energy consumption in the United Kingdom with a similar amount in China. We analyze heat pumps and district thermal energy network for efficient buildings. Their advantages are examined (i.e., flexibility in choosing heat sources, reduction of fuel consumption and increased environmental quality, enhanced community energy management, reduced costs for end users) together with their drawbacks, when they are intended as means for efficient building heating and cooling. Methodology/approach A literature review observed a range of operating conditions and challenges associated with the efficient operation of district heating and cooling networks, comparing primarily the UK’s and China’s experiences, but also acknowledging the areas of expertise of European, the United States, and Japan. It was noted that the efficiency of cooling networks is still in its infancy but heating networks could benefit from lower distribution temperatures to reduce thermal losses. Such temperatures are suitable for space heating methods provided by, for example, underfloor heating, enhanced area hydronic radiators, or fan-assisted hydronic radiators. However, to use existing higher temperature hydronic radiator systems (typically at a temperatures of >70°C) a modified heat pump was proposed, tested, and evaluated in an administrative building. The results appears to be very successful. Findings District heating is a proven energy-efficient mechanism for delivering space heating. They can also be adaptable for space cooling applications with either parallel heating and cooling circuits or in regions of well-defined seasons, on flow and return circuit with a defined change-over period from heating to cooling. Renewable energy sources can provide either heating or cooling through, for example, biomass boilers, photovoltaics, solar thermal, etc. However, for lower loss district heating systems, lower distribution temperatures are required. Advanced heat pumps can efficiently bridge the gap between lower temperature distribution systems and buildings with higher temperature hydronic heating systems Originality/value This chapter presents a case for district heating (and cooling). It demonstrates the benefits of reduced temperatures in district heating networks to reduce losses but also illustrates the need for temperature upgrading where building heating systems require higher temperatures. Thus, a novel heat pump was developed and successfully tested.