High Heat Production Research Articles

Occurrence types and genesis models of hot dry rock resources in China

As a significant part of geothermal resources, the hot dry rock (HDR) resources have drawn more and more attentions because it potentially can provide clean, stable, and huge potential of high-temperature geothermal energy. China started research on HDR resources since 1990s, relatively later than advanced countries. Until now, researches on the genetic mechanisms and the occurrence of HDR resources are still inadequate, which hinders the exploration and precise potential estimation of HDR resources in China. Based on the geological indicators of the occurrence of HDR resources, by combining the genetic analysis of HDR resources in the world and crustal structure in China, we classified the HDR resources into four types, i.e., the high radioactive heat production type, the sedimentary basin type, the modern volcano type, and the inner-plate active tectonic zone type. This classification could provide geological guidance for HDR resource targeting in certain areas and facilitate further developments.

Innovative Hybrid CHP systems for high temperature heating plant in existing buildings

This paper deals with the potential role of new hybrid CHP systems application providing both electricity and heat which are compatible with the building architectural and landscape limitations. In detail, three different plant layout options for high temperature heat production along with the electricity generation were investigated and compared each other. To do so, conventional natural gas CHPs and back up boiler, two-stage Electric Heat Pumps (EHPs) and trans-critical CO2 electric heat pump (CO2-HP) have been considered as reference technologies to build hybrid systems. In addition, hybrid solar collectors (PV/T) thermal output, along with the recovered low-grade heat from CHP exhaust gas, flowing to the stack, have been used as the CO2-HP low temperature driving source.

Growing lettuce under multispectral light-emitting diodes lamps with adjustable light intensity

Light-Emitting Diodes (LEDs) technology offers vast possibilities in plant lighting due to its ability to mix different light frequencies, high energy use efficiency and low heat production combined to long lifespan. In particular, the combined effect of the Blue:Red (B:R) ratio and other frequencies in the central part of the PAR spectrum (CGA, <em>i.e.</em> cyan, green and amber) may be very important, though literature information is scarce. In this paper, the effects of six light spectra from LED technology were tested, <em>i.e.</em>: (i) B:R=0.82 (<em>i.e.</em> similar to sunlight) with CGA (treatment T0), (ii) B:R=0.82 without CGA (T1), (iii) red prevalence (B:R=0.25) without CGA (T2), (iv) blue prevalence (B:R=4) without CGA (T3), (v) red prevalence with CGA (T4) and (vi) blue prevalence with CGA (T5). The experiment was carried out in a walk-in climatic chamber with controlled temperature and relative humidity and an incident PAR photon flux density (PFD) of 300 μmol m<sup>–2</sup> s<sup>–1</sup> (14/10 light/dark photoperiod), generated by multispectral LED lamps with adjustable light intensity. Smooth leaved lettuce (Lactuca sativa L. cv Gentilina) was used as the test plant and biomass yield (DW, g m<sup>–2</sup>), LAI, soil coverage proportion (SC%), energy-biomass conversion efficiency (E-BCE, kWh g<sup>–1</sup>) and Radiation Use Efficiency (RUE, g mol<sup>–1</sup> photons) were determined. Treatments with red predominance (T2 and T4) showed the highest SC% rates, while those with blue predominance (T3 and T5) showed the lowest. Light spectrum also affected leaf size (<em>i.e. </em>mean leaf area). The highest DW and RUE were observed in T2 and T4, followed by T0, while biomass in T3 and T5 was significantly lower (similar to T1). LAI values were generally high, but treatments with blue predominance showed the lowest LAI values (both with or without CGA). The introduction of intermediate wavelengths (green, cyan and amber) did not bring about significant improvement in DW or RUE, but resulted in reduced energy-biomass conversion efficiency, mainly due to lower architectural efficiency of the CGA LEDs. Future research should clarify how to optimise the light spectra according to the crop growth phases. The adoption of spectra promoting fast growth is fundamental in the early growth, while the use of spectra maximising yield quality may be more important later on.

Heat flow, heat production, and crustal temperatures in the Archaean Bundelkhand craton, north‐central India: Implications for thermal regime beneath the Indian shield

AbstractHeat flow and heat production data sets constrain the crustal thermal structure in the 2.5–3.5 Ga Bundelkhand craton, the oldest cratonic core in northern Indian shield, for the first time and allow comparisons with the southern Indian shield. Temperature measurements carried out in 10 boreholes at five sites in the craton, combined with systematic thermal conductivity measurements on major rock types, yield low heat flow in the range of 32–41 mW m−2, which is distinct from the generally high heat flow reported from other parts of the northern Indian shield. Radioelemental measurements on 243 samples of drill cores and outcrops reveal both large variability and high average heat production for the Neo‐Archaean to Palaeo‐Proterozoic granites (4.0 ± 2.1 (SD) μW m−3) relative to the Meso‐Archaean tonalite‐trondhjemite‐granodiorite (TTG) gneisses (2.0 ± 1.0 (SD) μW m−3). On the basis of new heat flow and heat production data sets combined with available geological and geophysical information, a set of steady state, heat flow‐crustal heat production models representative of varying crustal scenarios in the craton are envisaged. Mantle heat flow and Moho temperatures are found to be in the range of 12–22 mW m−2 and 290–420°C, respectively, not much different from those reported for the similar age Dharwar craton in southern India. This study reveals similar mantle thermal regimes across the northern and southern parts of the Indian shield, in spite of varying surface heat flow regimes, implying that much of the intraprovince and interprovince variations in the Indian shield are explained by variations in upper crustal heat production.

Effects of breeder age, strain, and eggshell temperature on nutrient metabolism of broiler embryos

Breeder age and broiler strain influence the availability of nutrients and oxygen through yolk size and eggshell conductance, and the effects of these egg characteristics on nutrient metabolism might be influenced by eggshell temperature (EST). This study aims to determine effects of breeder age, strain, and EST on nutrient metabolism of embryos. A study was designed as a 2×2 × 2 factorial arrangement using four batches of in total 4,464 hatching eggs of 2 flock ages at 29 to 30 wk (young) and 54 to 55 wk (old) of Ross 308 and Cobb 500. EST of 37.8 (normal) or 38.9°C (high) was applied from incubation day 7 (E7) until hatching. Wet yolk weight was determined mainly by breeder age (P = 0.043). Energy content in yolk (P = 0.004) and albumen + yolk (P = 0.005) were higher in old flock eggs than in young flock eggs, but did not differ between broiler strains. Eggshell conductance was higher in Ross 308 eggs than in Cobb 500 eggs (P < 0.001). Old flock embryos used more energy (P = 0.046) and accumulated more energy into yolk free body mass (YFBM; P = 0.030) than young flock embryos, whereas heat production (HP), energy lost, and efficiency of converting energy used to YFBM (EYFB) did not differ. Ross 308 embryos used more energy (P = 0.006), had a higher energy lost (P = 0.010), and a higher HP between E15 to E18 (P < 0.05) than Cobb 500 embryos. Energy content in YFBM did not differ between strains and EYFB (P = 0.024) was lower in Ross 308 than in Cobb 500. High EST resulted in higher HP than low EST from E11 to E15 (P < 0.05), but not after E15. Amount of energy used (P = 0.006) and energy accumulated in the YFBM (P < 0.001) was lower for embryos incubated at an EST of 38.9 than that of 37.8°C, whereas EYFB did not differ. In conclusion, breeder age, broiler strain, and EST differentially influence embryonic metabolism and particularly the availability of oxygen could have contributed to these differences.

Simulation of a 2 MW PEM Fuel Cell Plant for Hydrogen Recovery from Chlor-Alkali Industry

Some chemical processes, like the chlor-alkali production, generate significant amount of hydrogen as byproduct whose recovery within the chemical plant is not always possible. An efficient and attractive use of hydrogen is obtained installing a PEM fuel cell-based cogeneration unit, whose electricity and heat production covers part of plant consumptions. Practical application of this concept requires scaling up the fuel cell plant up to the multi-MW scale, an ongoing process with many open challenges where the development of dedicated modeling tools allows evaluating the plant expected performances and optimizing its operational strategies. This work presents the results of a the simulation activity modeling of an innovative 2 MW PEM fuel cell power plant, developed within the European project DEMCOPEM-2MW. Simulations are performed with ASPEN Plus®, including a specifically developed lumped model for the stacks in order to investigate their behavior as function of inlet streams conditions and of power set point. The BOP is modeled with particular attention to component expected operating conditions, efficiency, auxiliary consumption, pressure drops. The model is calibrated and validated on data from PEM stacks operated by Nedstack and MTSA in previous installations. Stacks model performs lumped energy and mass balances according to regressed polarization curves; cells decay is modeled through simplified assumptions aiming at evidencing the impact on auxiliaries operation and on global efficiency. Comparison with a different arrangement where excess hydrogen exiting the fuel cell anode is oxidized in a combustor, instead of being recirculated to the fuel cell, is also set up evidencing the possibility to increase the heat to electricity ratio and allow high temperature heat production. The model also allows assessing and optimizing the plant operational strategies (e.g. minimizing the power production and efficiency losses vs. lifetime), evaluating the deviations of real plant behavior from theoretical conditions.

Overview of ITER TBM program objectives and management

One of the most important ITER missions is to test tritium breeding blanket (TBB) concepts that would result in tritium self-sufficiency, an extraction of high grade heat and net electricity production in future fusion reactors. Knowledge of the TBB performance characteristics in the integrated fusion nuclear environment is essential to designing the TBB of the DEMO and the fusion reactor. Three equatorial ports in ITER are allotted for testing test blanket modules (TBMs), which are mock-ups of the TBB, allowing up to six TBMs to be simultaneously installed and tested – two TBMs per each port. Conceptual designs for all TBM systems are now completed, and the important next milestones are the achievement of the preliminary and the final design by 2025. The TBM systems will be installed during Assembly Phase III, which is planned to start in 2030, and tested during the ITER Pre-Fusion Power Operation 2, which is planned to start in 2032. This paper describes the objectives and management aspects of the TBM Program. Copyright © 2017 John Wiley & Sons, Ltd.

Evaluation of Exotically-Derived Soybean Breeding Lines for Seed Yield, Germination, Damage, and Composition under Dryland Production in the Midsouthern USA.

Although the Early Soybean Production System (ESPS) in the Midsouthern USA increased seed yield under irrigated and non-irrigated conditions, heat stress and drought still lead to poor seed quality in heat sensitive soybean cultivars. Our breeding goal was to identify breeding lines that possess high germination, nutritional quality, and yield potential under high heat and dryland production conditions. Our hypothesis was that breeding lines derived from exotic germplasm might possess physiological and genetic traits allowing for higher seed germinability under high heat conditions. In a 2-year field experiment, breeding lines derived from exotic soybean accessions, previously selected for adaptability to the ESPS in maturity groups (MG) III and IV, were grown under non-irrigated conditions. Results showed that three exotic breeding lines had consistently superior germination across 2 years. These lines had a mean germination percentage of >80%. Two (25-1-1-4-1-1 and 34-3-1-2-4-1) out of the three lines with ≥80% germination in both years maintained high seed protein, oleic acid, N, P, K, B, Cu, and Mo in both years. Significant (P < 0.05) positive correlations were found between germination and oleic acid and with K and Cu in both years. Significant negative correlations were found between germination and linoleic acid, Ca, and hard seed in both years. There were positive correlations between germination and N, P, B, Mo, and palmitic acid only in 2013. A negative correlation was found between germination and green seed damage and linolenic acid in 2013 only. Seed wrinkling was significantly negatively correlated with germination in 2012 only. A lower content of Ca in the seed of high germinability genotypes may explain the lower rates of hard seed in those lines, which could lead to higher germination. Many of the differences in yield, germination, diseases, and seed composition between years are likely due to heat and rainfall differences between years. The results also showed the potential roles of seed minerals, especially K, Ca, B, Cu, and Mo, in maintaining high seed quality. The knowledge gained from this research will help breeders to select for soybean with high seed nutritional qualities and high germinability.

Climate conditions, workplace heat and occupational health in South-East Asia in the context of climate change.

Occupational health is particularly affected by high heat exposures in workplaces, which will be an increasing problem as climate change progresses. People working in jobs of moderate or heavy work intensity in hot environments are at particular risk, owing to exposure to high environmental heat and internal heat production. This heat needs to be released to protect health, and such release is difficult or impossible at high temperatures and high air humidity. A range of clinical health effects can occur, and the heat-related physical exhaustion leads to a reduction of work capacity and labour productivity, which may cause substantial economic losses. Current trends in countries of the World Health Organization South-East Asia Region are towards higher ambient heat levels during large parts of each year, and modelling indicates continuing trends, which will particularly affect low-income individuals and communities. Prevention activities need to address the climate policies of each country, and to apply currently available heat-reducing technologies in workplaces whenever possible. Work activities can be adjusted to reduce exposure to daily heat peaks or seasonal heat concerns. Application of basic occupational health principles, such as supply of drinking water, enforcement of rest periods and training of workers and supervisors, is essential.

Air-conditioning system with underfloor air distribution integrated solar chimney in data center

Data centers have the characteristics of high heat production from equipment and uneven temperature distribution. Thus, in order to improve the thermal environment in data centers, this paper puts forward an air-conditioning system with under-floor integrated solar chimney. The improved system can also reduce energy consumption due to annual cooling. A typical data center model is built and verified with experiments. Based on this model, the new model integrated solar chimney is built and simulated. The results show that after integrating the solar chimney, the heat island effect impairs and the temperature of all compared points have a decline, which reached an average decline of about 4.4 ℃. In addition, integrated solar chimney system improves the mixing of cold air and hot air effectively.

Exploration of the enhanced geothermal system (EGS) potential of crystalline rocks for district heating (Elbe Zone, Saxony, Germany)

This paper addresses aspects of a baseline geothermal exploration of the thermally quiescent Elbe Zone (hosting the cities of Meissen and Dresden) for a potential deployment of geothermal heat in municipal heating systems. Low-permeable to impermeable igneous and metamorphic rocks constitute the major rock types at depth, implying that an enhanced geothermal system needs to be developed by creating artificial flow paths for fluids to enhance the heat extraction from the subsurface. The study includes the development of geological models for two areas on the basis of which temperature models are generated at upper crustal scale. The models are parameterized with laboratory-measured rock thermal properties (thermal conductivity k, radiogenic heat production H). The uncertainties of modelled temperature caused by observed variations of k and H and inferred mantle heat flow are assessed. The study delineates highest temperatures within the intermediate (monzonite/syenite unit) and mafic rocks (diorite/monzodiorite unit) forming the deeper portions of the Meissen Massif and, specifically for the Dresden area, also within the low-metamorphic rocks (slates/phyllites/quartzites) of the Elbtalschiefergebirge. Boreholes 3–4 km deep need to be drilled to reach the envisioned economically favourable temperatures of 120 °C. The metamorphic and mafic rocks exhibit low concentrations of U and Th, thus being advantageous for a geothermal use. For the monzonite/syenite unit of high heat production (~6 µW m−3) in the Meissen Massif, the mobilization of Th and U into the geothermal working fluid is assumed to be minor, although their various radioactive decay products will be omnipresent during geothermal use.

The deep thermal field of the Upper Rhine Graben

The Upper Rhine Graben has a significant socioeconomic relevance as it provides a great potential for geothermal energy production. The key for the utilisation of this energy resource is to understand the controlling factors of the thermal field in this area. We have therefore built a data-based lithospheric-scale 3D structural model of the Upper Rhine Graben and its adjacent areas. In addition, 3D gravity modelling was performed to constrain the internal structure of the crystalline crust consistent with seismic information. Based on this lithosphere scale 3D structural model the present-day conductive thermal field was calculated and compared to measured temperatures. Our results show that the regional thermal field is mainly controlled by the configuration of the upper crust, which has different thermal properties characteristic for the Variscan and Alpine domains. Temperature maxima are predicted for the Upper Rhine Graben where thick insulating Cenozoic sediments cause a thermal blanketing effect and where the underlying crustal units are characterised by high radiogenic heat production. The comparison of calculated and measured temperatures overall shows a reasonable fit, while locally occuring model deviations indicate where a larger influence of groundwater flow may be expected.

Validity of inner canthus temperature recorded by infrared thermography as a non-invasive surrogate measure for core temperature at rest, during exercise and recovery

Research into obtaining a fast, valid, reliable and non-invasive measure of core temperature is of interest in many disciplinary fields. Occupational and sports medicine research has attempted to determine a non-invasive proxy for core temperature particularly when access to participants is limited and thermal safety is of a concern due to protective encapsulating clothing, hot ambient environments and/or high endogenous heat production during athletic competition. This investigation aimed to determine the validity of inner canthus of the eye temperature (TEC) as an alternate non-invasive measure of intestinal core temperature (TC) during rest, exercise and post-exercise conditions. Twelve physically active males rested for 30min prior to exercise, performed 60min of aerobic exercise at 60% V̇O2max and passively recovered a further 60min post-exercise. TEC and TC were measured at 5min intervals during each condition. Mean differences between TEC and TC were 0.61°C during pre-exercise, −1.78°C during exercise and −1.00°C during post-exercise. The reliability between the methods was low in the pre-exercise (ICC=0.49 [−0.09 to 0.82]), exercise (ICC=−0.14 [−0.65 to 0.44]) and post-exercise (ICC=−0.25 [−0.70 to 0.35]) conditions. In conclusion, poor agreement was observed between the TEC values measured through IRT and TC measured through a gastrointestinal telemetry pill. Therefore, TEC is not a valid substitute measurement to gastrointestinal telemetry pill in sports and exercise science settings.

Research on Formation Mechanisms of Hot Dry Rock Resources in China

AbstractAs an important geothermal resource, hot dry rock (HDR) reserves have been studied in many countries. HDR resources in China have huge capacity and have become one of the most important resources for the potential replacement of fossil fuels. However, HDR resources are difficult to develop and utilise. Technologies for use with HDR, such as high‐temperature drilling, reservoir characterisation, reservoir fracturing, microseismic monitoring and high‐temperature power stations, originate from the field of oil and drilling. Addressing how to take advantage of these developed technologies is a key factor in the development of HDR reserves. Based on the thermal crustal structure in China, HDR resources can be divided into four types: high radioactive heat production, sedimentary basin, modern volcano and the inner‐plate active tectonic belt. The prospective regions of HDR resources are located in South Tibet, West Yunnan, the southeast coast of China, Bohai Rim, Songliao Basin and Guanzhong Basin. The related essential technologies are relatively mature, and the prospect of HDR power generation is promising. Therefore, analysing the formation mechanisms of HDR resources and promoting the transformation of technological achievements, large‐scale development and the utilisation of HDR resources can be achieved in China.

High Quality Characteristics of Briquette Fuel Based on Physical Appearances and Electrical Induction

At present, charcoal briquette fuel, a source of heat energy and mostly made from agricultural waste materials, are popular in the markets because of their high constant heat output. It helps reduce pollution, and produce no sparks while burning, but varied due to different types of materials, burning protocols, temperature, and pressure used. In this study, the research team have studied the characteristics of high quality fuel briquettes for possible further development of standard indicators of briquette fuel production process. In the study, key factors of the Charcoal fuel features composed of high qualities of physical characteristics and electrical induction. Activated carbon and coconut shell charcoal types were showed to be great materials. The production process involved aerobic burning at 800-900oC for at least 3 hours, grinding and mixing with starch binder. The briquettes’ electrical conductivity was especially lower than 10 kΩ. High heat production was obtained at least 6000 Cal/g while ground charcoal possessed with the sizes were varied. Under microscopy, the charcoal particle sizes were in a range of 50-100 μm for 30-50% (w/w), size of 10-50 μm for 20-40% (w/w) and distinctive numbers of holes greater than 300 μ to 1 mm were rarely observed. Therefore, with key characteristics of charcoal briquette fuel, it could be further applied for development the indicator as well as instruments to measure the quality of the briquette.

Climate change and the loss of organic archaeological deposits in the Arctic.

The Arctic is warming twice as fast as the global average with overlooked consequences for the preservation of the rich cultural and environmental records that have been stored for millennia in archaeological deposits. In this article, we investigate the oxic degradation of different types of organic archaeological deposits located in different climatic zones in West and South Greenland. The rate of degradation is investigated based on measurements of O2 consumption, CO2 production and heat production at different temperatures and water contents. Overall, there is good consistency between the three methods. However, at one site the, O2 consumption is markedly higher than the CO2 production, highlighting the importance of combining several measures when assessing the vulnerability of organic deposits. The archaeological deposits are highly vulnerable to degradation regardless of age, depositional and environmental conditions. Degradation rates of the deposits are more sensitive to increasing temperatures than natural soils and the process is accompanied by a high microbial heat production that correlates significantly with their total carbon content. We conclude that organic archaeology in the Arctic is facing a critical challenge that requires international action.

Heat flow–heat production relationship not found: what drives heat flow variability of the Western Canadian foreland basin?

Heat flow high −80 ± 10 mW/m2 in the northern western parts of the Western Canadian foreland basin is in large contrast to low heat flow to the south and east (50 ± 7 mW/m2) of the same basin with the same old 2E09 year’s Precambrian basement and some 200-km-thick lithosphere. Over-thrusted and flat-laying sedimentary units are heated from below by heat flow from the old craton’ crust and low 15 ± 5 mW/m2 mantle contribution. The heat flow vs. radiogenic heat production statistical relationship is not found for this area. To account for this large heat flow contrast and to have 200-km-thick lithosphere, we would need to assume that high heat production layer of the upper crust varies in thickness as much as factor of 2 and/or that the measured heat production at top of Precambrian basement is not representative for deeper rocks. The other explanation proposed before that heat in the basin is redistributed by the regional fluid flow systems driven from high hydraulic head areas close to the foothills of the Rocky Mountains toward low elevation areas to the east and north cannot be explained by observed low Darcy fluid velocities and the geometry of the basin.

The origin of extensive Neoarchean high-silica batholiths and the nature of intrusive complements to silicic ignimbrites: Insights from the Wyoming batholith, U.S.A.

Extensive intrusions composed entirely of biotite granite are common in Neoarchean cratons. These granites, which have high silica and potassium contents, are not associated with intermediate and mafic phases. One such Neoarchean granite batholith, herein named the Wyoming batholith, extends more than 200 km across central Wyoming in the Granite and the Laramie Mountains. From field characterization, petrology, geochemistry, and Nd isotopic data we establish that the magnesian Wyoming batholith exhibits continental arc chemical and isotopic signatures. It is best interpreted as a large, upper crustal silicic batholith that likely formed when the subducting oceanic plate steepened or foundered, bringing mantle heat and mass to the base of the crust. Similar Cenozoic settings, such as the Altiplano-Puna plateau of the Andes and the volcanic provinces of the western United States, host large volumes of silicic ignimbrite. The magma chambers supplying these eruptions are inferred to be silicic, but the structural, petrologic, and geochemical details are unknown because the batholiths are not exposed. We suggest that the Wyoming batholith represents an analog for the plutonic complex underlying these ignimbrite systems, and provides an opportunity to examine the shallow magma chamber directly. Our work establishes that, aside from more leucocratic margins, the sill-like magma chamber is petrologically and chemically homogeneous, consistent with effective mixing by vertical convection. Nd isotopic variations across the batholith indicate that horizontal homogenization is incomplete, preserving information about the feeder system to the batholith and variations in magma sources. The late Archean Earth may present optimal conditions for the formation of extensive granite batholiths like the Wyoming batholith. By this time the majority of the planet’s continental crust had formed, providing the environment in which differentiation, distillation, and assimilation could occur. Moreover, the Neoarchean Earth’s relatively high radioactive heat production provided the power to drive these processes.

A computational study of DME-methanol fractions with controlling several factors on HCCI combustion

Two-stage fuel and single stage fuel have different effects on ignition delay and other combustion characteristics. If we mix two fuels with variable fractions, combustion characteristics will be represented with dependence on the fraction. We first investigated the change of combustion characteristics and combustion ranges by dimethyl ether (DME)/methanol fraction, IVC temperature and IVC pressure. By increasing methanol fraction, Heat release rate (HRR) showed higher rate than the case containing less methanol after 1250 K. However, it didn’t mean that Accumulated heat release (AHR) was also higher than the cases which contained less methanol. AHR of D90/M10 was the first case which surpassed AHR of D100 at about 1808K, and D80/M20 surpassed D100 at about 2318K. The result was caused by change of reaction mechanism and the change was remarkably shown in the Thermal ignition preparation (TIP) range and the Thermal ignition (TI) range. Above all, strengthened H2O2 Loop reactions affected heat production to increase in TIP range, and also one of the loop reactions, CH2O + OH = HCO + H2O, quickly produced formyl radical with increase of net reaction rate by methanol. Those results naturally led to higher reaction rates of HCO-CO-CO2 oxidation with higher heat production. As a result, D50/M50 case showed the highest maximum Pressure rise rate (PRR). Furthermore, dispersion rate of PRR was increased by increasing methanol fraction in the range which was from back end of TIP to forepart of TI range. Finally, we focused the reaction paths of two fuels and the production and consumption rate of main radicals on the basis of combustion ranges such as LTO, Negative temperature coefficient (NTC), Thermal ignition preparation (TIP) and Thermal ignition (TI) to understand the results of this study.

The Cornubian geothermal province: heat production and flow in SW England: estimates from boreholes and airborne gamma-ray measurements

The Cornubian granite batholith provides one of the main high heat production and flow provinces within the UK. An extensive programme of borehole measurements was undertaken in the 1980s to characterise the geothermal resource. Here we revisit the published data on heat flow and heat production from 34 boreholes and revise the published heat flow values in accord with modern palaeoclimate knowledge. This leads to a more rigorous (and increased) set of estimated temperatures at depth across the granite outcrops. Predicted temperatures at a depth of 5 km largely exceed 200 °C and are 6–11 % higher than previously estimated values. We also reconsider the borehole heat production values in conjunction with new heat generation information from a recent regional-scale airborne geophysical survey. The radiometric (gamma-ray) data provide detailed (~70 m along-line) ground concentration estimates of the heat-producing radioelements. These are then combined to estimate heat production in the near surface. The airborne estimates are subject to attenuation by the soil profile. Here we demonstrate and then adopt an assumption that the observations of the soil–bedrock medium undergo a flux attenuation by a factor of about two compared to the response of the underlying material. The revised estimates are then correlated with their equivalent deeper borehole estimates. Linear regression is then used to correct the shallow airborne estimates to values that are consistent with the deeper borehole determinations. The procedure provides a detailed and extensive mapping of heat production at both on- and off-granite locations across SW England. The Dartmoor and Land’s End granite offer the greatest spatial geothermal potential in terms of their intrinsic radionuclide concentrations and associated heat production. District-scale heat production is studied using the airborne data acquired uniformly across conurbations. The analysis identifies the towns of Camborne, Penzance, St. Austell, Redruth and St Ives as having relatively high values (>4 μW m−3) within their urban perimeters.