Local Boiler Research Articles

Simulation of micro-CHP diffusion by means of System Dynamics

This paper presents a simulation analysis with System Dynamics of the possible diffusion of micro-systems for combined heat-power generation ( μ-CHP) as a substitute for centralised electricity generation and local boilers in the residential sector. Decentralised energy production is an important challenge in the 21st century to respond to the threats of exhaustion of non-renewable resources, and of global pollution. The purpose of the System Dynamics modelling is to show the difficulties μ-CHP faces, like most innovative technologies, mainly due to its high investment costs. Feedbacks are important in modelling the diffusion process of this technology and the fundamental aspect of learning effects on the cost decrease. The consumer model is based on the replacement of traditional boilers by μ-CHP installations using the Bass diffusion model. It is shown that natural economic forces are probably not sufficient to achieve a sustained growth. Several incentive schemes to be implemented by the regulatory authorities are investigated to promote this technology.

ESTIMATION OF THE EFFECTIVENESS OF RENOVATION WORK IN LITHUANIAN SCHOOLS

The aim of this work was to estimate the effectiveness of the renovation work that was carried out in 63 Lithuanian schools by disclosing the main renovation works, analysing changes in the amount of the energy used for the heating after renovation. Reduction of the windows area with shields, replacement of old doors and windows with the new ones were the most frequent renovation works in the tested schools. 52 % of respondents indicated condensation on windows after the renovation work. The indoor temperature of the schools increased from 15 °C to 18 °C. Also, the energy consumptions for the heating of the schools was lowered by 17 % in schools with district heating system and by 22 % in schools with local boiler house.

External costs and taxes in heat supply systems

A systems approach was used to compare different heating systems from a consumer perspective. The whole energy system was considered from natural resources to the required energy services. District heating, electric heat pumps, electric boilers, natural-gas-, oil- or pellet-fired local boilers were considered when supplying heat to a detached house. The district heat production included wood-chip-fired and natural-gas-fired cogeneration plants. Electricity other than cogenerated electricity was produced in wood-chip- and natural-gas-fired stand-alone power plants. The analysis includes four tax scenarios, as well as the external cost of environmental and health damage arising from energy conversion emission based on the ExternE study of the European Commission. The most cost-efficient systems were the natural-gas and oil boiler systems, followed by the heat pump and district heating systems, when the external cost and taxes were excluded. When including the external costs of CO 2 emission, the wood-fuel-based systems were much more cost efficient than the fossil-fuel-based systems, also when CO 2 capture and storage were applied. The external costs are, however, highly uncertain. Taxes steer towards lowering energy use and lowering CO 2 emission if they are levied solely on all the fossil-fuel-related emission and fuel use in the systems. If consumer electricity and heat taxes are used, the taxes have an impact on the total cost, regardless of the fuel used, thereby benefiting fuel-based local heating systems. The heat pump systems were the least affected by taxes, due to their high energy efficiency. The electric boiler systems were the least cost-efficient systems, also when the external cost and taxes were included.

Polish-Dutch Cooperation in the Szamotuły Joint Implementation Project

In this paper the modernisation of two coal boiler plants for district heating in Szamotuły near Poznań is described. This involved the first joint Polish-Dutch venture aiming at the protection of the natural environment and the efficient production of electric and heat energy. Energetyka Poznańska SA, represented by COGEN, a subsidiary acting on its behalf, the Management of the City and Commune of Szamotuly and Essent Duurzaam, a Dutch company, jointly adhered to this pilot programme of modernization of local coal boiler houses. Financial support was granted by SENTER, the Dutch government agency, in the framework of a JOINT-IMPLEMENTATION programme for the purpose of the global limitation of greenhouse gas emission.

A system perspective on the heating of detached houses

Primary energy use, emission and the cost of whole energy system chains, from natural resource to end-user, were analysed, in a Swedish context, when heating detached houses. Both electricity-based systems employing heat pumps, boilers, or resistance heaters, and local fuel-based systems (e.g. natural gas, oil and wood fuel) were considered. The base-load electricity was produced in stand-alone power plants using wood fuel or natural gas, while peak-load electricity and fuel used for transportation were produced from crude oil. The heat pump systems were most energy efficient, followed by the local fuel-based systems. Electricity production based on cogeneration instead of stand-alone power plants would improve the energy efficiency and reduce the cost of the electricity-based systems. The wood-fuel-based systems emitted about one tenth of the carbon dioxide emitted by the fossil-fuel systems. The acidic emission, however, was higher for wood-fuel-based systems, especially compared with natural gas. Primary energy use and emission from the recovery, production and transportation of fuels were limited compared with the primary energy use and emission for the whole energy system chains. Transportation of biofuels, for example, represented less than 1% of the primary energy use. The heat pump systems and the local boiler systems, excluding the pellet boiler system, exhibited the lowest cost. The cost of electricity-based systems, other than heat pump systems, was higher due to a lower overall conversion efficiency. The pellet boiler system exhibited almost as high cost as these electric-based systems. The difference in cost between the same type of wood-fuel- and fossil-fuel-based systems was less than 12%. All Swedish energy taxes and environmental fees were excluded in the cost calculations. The removal of carbon dioxide from the flue gases from large natural-gas-fired stand-alone power plants could reduce the carbon dioxide emission by about 70%. This will increase the primary energy use, the emission of other compounds and the cost. However, regarding heat pumps these increases are small due to the high coefficient of performance.

Should existing pressure vessel regulations apply to gas filled electrical equipment-an electrical engineer's viewpoint

Electrical equipment which uses an inert gas, sulfur hexafluoride, has been in commercial use for several decades and is today the most dominant design technology for high-voltage substation equipment. Sulfur hexafluoride gas possesses excellent electrical-insulation and arc-quenching properties. making it suitable for the design of circuit breakers, instrument transformers, bus ducts, and total gas-insulated metal-clad substations (GIS). The gas properties require that only modest equipment design pressures of 400 to 700 kPa (60 to 102 psig) be used. However. these pressures are sufficient to classify the equipment as a pressure vessel under many local boiler and pressure-vessel safety laws. New CENELEC standards, written specifically for this gas-filled equipment, should provide a logical basis for the future electrical industry regulation of this specialized equipment.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Hydrogen and nuclear power

Demonstrating that an electricity supply system depending on nuclear fuel for the primary energy input can always benefit from some synthesis of a chemical fuel such as hydrogen, the author compares the benefits of using hydrogen within the electricity supply system with those of using it outside the system, in local boilers and prime movers. He concludes that over a wide range of circumstances there is a case for a hydrogen supply system linked with the electricity supply. A tentative estimate suggests the size of the industry might be similar to the existing natural gas industry.