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A methodology for the CIS (Geographic Information System) based analysis of DH (District Heating) potentials is introduced and applied to the continental United States. The energy demand for space heating and hot water in the resi...
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A methodology for the CIS (Geographic Information System) based analysis of DH (District Heating) potentials is introduced and applied to the continental United States. The energy demand for space heating and hot water in the residential and commercial sector is assessed and spatially allocated using high resolution population distribution and land use data. Demand centers are identified and the overall heat demand and its density are extracted. For each of some 4800 agglomerations, average heat distribution costs are calculated and a CHP (combined heat and power) plant suitable in technology and capacity is selected. The results suggest that there is substantial potential for an extension of DH in the United States. Especially in the north eastern part of the country, a significant share of the demand is located in areas of high demand density. Heat distribution costs vary considerably, and are on average slightly lower in greater agglomerations and regions with high specific heat demands. The overall potential, its distribution to geographical regions and CHP technologies, as well as the average heat distribution costs are found to be strongly dependent on the assumed minimum heat demand density applied to classify the grid cells according their suitability for DH.
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We introduce the notion of harmonic map from a graph into a Riemannian manifold via a discrete version of the energy density. Existence and basic properties are established. Global existence and convergence of the associated heat ...
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We introduce the notion of harmonic map from a graph into a Riemannian manifold via a discrete version of the energy density. Existence and basic properties are established. Global existence and convergence of the associated heat flow are proved without any assumption on the curvature of the target manifold. We discuss a variant of the Steiner problem which replaces length by elastic energy. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
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District heating can provide cost-effective and tow-carbon energy to local populations, such as space heating in winter and year-round hot/cold water; this is also associated with electricity generation in combined-heat-and-power ...
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District heating can provide cost-effective and tow-carbon energy to local populations, such as space heating in winter and year-round hot/cold water; this is also associated with electricity generation in combined-heat-and-power systems. Although this is currently rare in the UK, many legislative policies, including the Renewable Heat Incentive, aim to increase the amount of energy from such sources; including new installations, as well as extending/upgrading existing distributed energy schemes. Sheffield already has an award-winning district energy network, incorporating city-wide heat distribution. This paper aimed to demonstrate the opportunities for expansions to this through geographical information systems software modelling for an in-depth analysis of the heat demands in the city. 'Heat maps' were produced, locating existing and emerging heat sources and sinks. Heat loads (industrial, commercial, educational, health care, council and leisure facilities/complex) total S3 MW, with existing residential areas accounting for ~1500 MW and new housing developments potentially adding a further 35 MW in the future. A number of current and emerging heat sources were also discovered - potential suppliers of thermal energy to the above-defined heat sinks. From these, six 'heat zones' where an expansion to the existing network could be possible were identified and the infrastructure planned for each development.
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Let M~m and N~n → R~k be two compact Riemannian manifolds without boundary. We consider the L~2 gradient flow for the energy F(u): = 1/2 ∫_M|Δu|~2. If m ≤ 3 or if m = 4 and F(u_0) is small, we show that the heat flow for extri...
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Let M~m and N~n → R~k be two compact Riemannian manifolds without boundary. We consider the L~2 gradient flow for the energy F(u): = 1/2 ∫_M|Δu|~2. If m ≤ 3 or if m = 4 and F(u_0) is small, we show that the heat flow for extrinsic biharmonic maps exists for all time, and that the solution subconverges to a smooth extrinsic biharmonic map as time goes to infinity.
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We consider the existence, uniqueness and convergence for the long time solution to theharmonic map heat equation between two complete noncompact Riemannian manifolds,where the target manifold is assumed to have nonpositive curvat...
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We consider the existence, uniqueness and convergence for the long time solution to theharmonic map heat equation between two complete noncompact Riemannian manifolds,where the target manifold is assumed to have nonpositive curvature. As a corollary, weshow that if the tension field is in L~p, the heat flow exists globally and uniquely whichconverges at infinity under an additional condition.
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We give a simple proof of the well-known Hamilton's result [1] on the heat flows and harmonic maps from manifolds with boundary using the approach of Ding-Lin[2].
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The ambitious policy in Denmark on having a 100% renewable energy supply in 2050 requires radical changes to the energy systems to avoid an extensive and unsustainable use of biomass resources. Currently, wind power is being expan...
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The ambitious policy in Denmark on having a 100% renewable energy supply in 2050 requires radical changes to the energy systems to avoid an extensive and unsustainable use of biomass resources. Currently, wind power is being expanded and the increasing supply of electricity is slowly pushing the CHP (combined heat and power) plants out of operation, reducing the energy efficiency of the DH (district heating) supply. Here, large heat pumps for district heating is a frequently mentioned solution as a flexible demand for electricity and an energy efficient heat producer. The idea is to make heat pump use a low temperature waste or ambient heat source, but it has so far been very unclear which heat sources are actually available for this purpose.
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Industrial Excess Heat (IEH) is an underutilised resource which could contribute to decarbonising the heat supply. It is particularly well suited for supplying district heat networks (DHN), thereby enabling the capture and distrib...
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Industrial Excess Heat (IEH) is an underutilised resource which could contribute to decarbonising the heat supply. It is particularly well suited for supplying district heat networks (DHN), thereby enabling the capture and distribution of excess energy from industries and incineration plants. However, as heat cannot be readily transported over long distances, there is a need to analyse the balance of supply and demand over time taking into account the geospatial constraints placed on the linking of IEH supplies and DHN demands. This work presents an analysis of the potential for the supply of DHN systems using high and low network temperatures by IEH in Switzerland. A spatial clustering method is used to link potential supplies and demands, and monthly supply and demand curves are used to calculate the potential for IEH supply subject to spatiotemporal constraints. A further analysis deals with the technical potential for seasonal storage to shift surplus IEH energy from summer to winter. A total resource of 12TWh/y of IEH was found, but spatial and temporal constraints limited its utilisation to between 7.7TWh/y and 10.5TWh/y depending the scenario considered. 17.4% of total heat demand could be supplied by IEH using low temperature DHN and seasonal storage.
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Heat waves and heat-related stresses are increasing environmental concerns in urban areas. The impact of heat waves is dependent on the intensity and duration of each event and on underlying environmental and socio-demographic fac...
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Heat waves and heat-related stresses are increasing environmental concerns in urban areas. The impact of heat waves is dependent on the intensity and duration of each event and on underlying environmental and socio-demographic factors which influence population vulnerability. In order to develop effective adaptation strategies, it is important to develop a method to clearly identify the most vulnerable areas based on these factors. The purpose of this study is to develop and map a heat wave vulnerability index combined with heat exposure analysis to identify areas where interventions can be targeted. The vulnerability index was derived from a principle component analysis of eight key variables that influence heat wave vulnerability. Eight proxy measures of vulnerability were obtained from 2010 census and land-use data for the 1904 census districts of Osaka City. Three principle components explained ＞77 % of the variance (age, employment and education; social isolation; density and lack of green space). The components were combined and weighted to produce a vulnerability score for each census district. The vulnerability scores ranged from 0 to 106, were categorised into eight vulnerability levels and were overlaid with fine-scale air temperature observations. The resulting output identified the distribution of population vulnerability and exposure. This assessment of vulnerability, combining exposure and sensitivity components, can provide precedent for efficient, targeted action to be taken to reduce the impact of heat waves at present and under climate change.
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We study blow-tip results for generalizations of the corotational harmonic map heat flow from the unit disk into the unit sphere. The generalizations include more general targets, composition with certain holomorphic maps, and cas...
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We study blow-tip results for generalizations of the corotational harmonic map heat flow from the unit disk into the unit sphere. The generalizations include more general targets, composition with certain holomorphic maps, and cases where the associated Dirichlet integral does not admit a finite lower bound. In the latter case, blow-tip events are irreversible.
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