On-site Heat Research Articles

A Highly Efficient Catalytic Co-Combustion of Aromatic and Oxygenated Volatile Organic Compounds (VOCs) via H2-Driven Onsite Heating

Catalytic combustion, a highly efficient technique for reducing volatile organic compounds (VOCs), is the focus of this study. We investigate the improved catalytic efficiency of the physical mixing of nanosized Pt and atomically dispersed Co, supported on Al2O3 catalysts (Pt-Co)/Al2O3 (PM) for the catalytic combustion of VOCs. The catalyst efficiency is evaluated for the hydrogen-assisted catalytic oxidation of various VOCs, including aromatic and oxygenated VOCs such as benzene, toluene, methanol, and formic acid. Our study aims to understand the impact of hydrogen incorporation on the combustion process of various VOCs. The findings of this work underscore the potential of hydrogen-assisted catalytic ignition, which can achieve ignition at ambient temperature, a significant departure from conventional electric heating that typically requires additional energy to raise the temperature. Various characterization techniques, such as BET, STEM, and XRD, are employed to assess the structure–activity relationship of the catalyst. The optimal hydrogen concentration for complete VOC conversion is 3%. Notably, even at a lower hydrogen concentration of 2%, benzene and methanol reach an ideal ignition temperature of over 500 °C when introduced into the physically mixed catalyst. This study highlights the significant potential of hydrogen-assisted catalytic combustion, inspiring further research and offering a promising method to reduce VOCs effectively.

Hydrogen-Ignited-Methanol Catalytic Co-Combustion of Aromatic Volatile Organic Compounds over PdPt/Al2O3 Bimetallic Catalyst

Electric heating is frequently employed to treat volatile organic compounds (VOCs) through catalytic combustion. However, it is associated with problems such as slow heating, high energy consumption, and low efficiency. This study explores PdPt/Al2O3 catalysts for igniting methanol (MeOH) through H2 catalytic combustion, providing internal on-site heating of catalyst active sites. It also investigates VOCs’ abatement using H2-ignited-MeOH combustion without H2 and external heating. Bimetallic catalysts enhance activity and reduce thermal aging. Hydrogen gas (H2) can initiate the MeOH combustion at room temperature with the addition of very small amounts, even below its low explosive limit of 4%. This process optimizes MeOH ignition at approximately 350 °C, even when the concentration of H2 is as low as 0.01%. This method enhances combustion kinetics, converting MeOH and VOCs into CO2 and water. Catalytic performance is independent of PdPt nanoparticle sizes in fresh and spent catalysts, represented in XRD and STEM. Using hydrogen as an igniting agent provides a clean, effective method to initiate catalytic reactions, addressing traditional challenges and enhancing VOCs’ decomposition efficiency.

Dual benefits of biofouling reduction in non-fed aquaculture: On-site heat treatment enhances oyster production and mitigates local environmental impacts

We experimentally evaluated the biofouling reduction by on-site heat treatment in enhancing oyster aquaculture production and mitigating its environmental impacts. Specifically, we compared oyster growth, settling flux of particulate organic matter (POM), and its oxygen consumption rate (OCR) between heat-treated (HT) and non-treated (N) sections within suspension oyster farms in a temperate bay. HT demonstrated a substantial reduction of 81–99% in fouling mussel biomass and approximately 20–30% increases in cultivated oysters’ growth and condition index. The settling flux of POM was 10–57% smaller in HT mainly due to the reduction in biodeposition from fouling mussels. However, OCR of settling POM at a unit mass was 6–62% higher in HT than in N; overall, the short-term oxygen consumption by settling POM did not significantly differ between HT and N. The increase in OCR of settling POM in HT may be attributable to the decrease in biodeposits from fouling organisms and increase in the relative contribution of fresh POM entering from unfarmed areas. Meanwhile, from the longer-term perspective, the substantial reduction in settling POM by the heat treatment lower the potential for oxygen consumption in the bottom layers over the half-year farming operation by 31%. In conclusion, on-site heat treatment is a simple tactic for controlling nutrient and POM flows at production sites, simultaneously enhancing oyster production and mitigating the local environmental impact of non-fed oyster aquaculture. Furthermore, this approach exemplifies an effective tactic to enhance the sustainability of primary food production processes.

Facile Abatement of Oxygenated Volatile Organic Compounds via Hydrogen Co-Combustion over Pd/Al2O3 Catalyst as Onsite Heating Source

Catalytic combustion of volatile organic compounds (VOCs) usually requires external energy input to hold the desired reaction temperature via electric heating. This work presents an example of internal onsite heating of the catalytic active sites via hydrogen catalytic combustion with air over a conventional Pd/Al2O3 catalyst. Hydrogen combustion was ignited by the catalyst at room temperature without electric heating, and thus the temperatures were readily varied with the concentrations of H2. Representative oxygenated VOCs such as methanol, formaldehyde and formic acid can be completely oxidized into CO2 and water by co-feeding with H2 below its low explosion limit of 4% using Pd/Al2O3 as shared catalyst. The catalytic performance apparently is not sensitive to the sizes of Pd nanoparticles in fresh and spent states, as revealed by XRD and STEM. This provides an option for using renewable green hydrogen to eliminate VOC pollutants in an energy-efficient way.

Theory and Engineering Practice of Intermittent Heat Injection-Enhanced Coalbed Methane Extraction.

Because of the strong adsorption characteristics of methane and the low permeability of coal seams, the extraction efficiency of coalbed methane (CBM) is very low. Here, based on the energy conservation equation, we propose the theory of heat injection-enhanced CBM extraction. We developed a device for heat injection-enhanced CBM extraction and performed an on-site heat injection test in the Chengzhuang coal mine. The results showed that when the water injection rate was 0.5 m3/h, the heat injection temperature was 145 °C, with two heat injections, yielding the best CBM extraction effect. This could fully utilize the heat injection equipment and achieve a fast, safe, and efficient extraction. The gas production law of the intermittent heat injection-enhanced CBM extraction method had obvious stages; the CBM concentration and daily gas production were very low during the heat injection stage but were greatly improved during the extraction stage after heat injection. The highest CBM concentration reached 100%, and the maximum daily gas production of CBM increased by 1269 times. The variation law of the cumulative gas production with time was fitted using Wang's empirical formula. Comparative analysis showed that, compared to traditional extraction, intermittent heat injection shortened the extraction time by 6.6 years. Compared with other enhanced CBM extraction methods, the intermittent heat injection method had obvious technical advantages and greater improvements in concentration and CBM extraction speed. Therefore, the results are of great significance for improving the recovery rate of CBM and for reducing greenhouse gas emissions.

Optimization of tree locations to reduce human heat stress in an urban park

Trees provide cooling benefits through shading and evapotranspiration; they are regarded as an important measure in heat-resilient urban planning and policies. Knowing where to plant trees for maximum cooling benefits, given practical and resource constraints, remains a challenge in both practice and research. Literature in the field of tree modeling and location optimization is limited, either by the incompleteness in accounting for tree shading, evapotranspiration, and the modifying effect of wind, or by the slow-running speed of the Computational Fluid Dynamics model, making them less applicable in practice. This paper describes a novel method to search for the optimal locations for trees to maximize their cooling benefits in an urban environment. A rapid simulation model was applied to assess on-site heat stress under the influences of trees, which was evaluated using field measurements conducted under hot, temperate, and cool weather conditions in an urban park in Hong Kong. It was then linked to a genetic algorithm in search of a near-optimal tree layout. The proposed method was tested in the same park, and it can automatically identify locations to plant new trees to minimize heat stress, subject to practical constraints such as avoiding existing buildings and utilities. It can also identify the optimal locations to rearrange the existing 55 trees, hypothetically, which can cool the park by up to 0.3 ℃ in on-site average equivalent temperature compared with the worse scenario. Trees can cool the most if they are concentrated on the leeward side of the park, rather than spread evenly. The proposed method runs significantly faster than existing approaches, and it can inform research and landscape design practices concerning park cooling as a goal.

Identification and classification of heat pump problems in the field and their implication for a user-centric problem recognition

Heat pumps are at the heart of the transition to sustainable heating in buildings. Yet, minor installation and setting errors add to unnoticed performance drops over the system’s lifetime. With the advent of smart meters that constantly measure electricity consumption, data patterns of heat pumps have become available, even for the many not connected to the Internet. These data hold the potential to monitor heat pumps continuously, identify issues, and thus assist energy consultants and heat pump owners in lifting hidden conservation potential. Yet, research and practice lack an overview of specific problems that could help in this task. In a mixed-method approach, this study investigated 228 protocols of on-site heat pump inspections in Switzerland and found 47 problem classes with varying frequencies. Based on this empirical data and expert interviews, a classification scheme for heat pump issues is proposed and validated. It uncovers the cause of problems, how and by whom they can be recognised and solved, and potential benefits. The work demonstrates that (i) several problems are likely to create smart meter patterns and that (ii) heat pump owners could be involved in the problem recognition and solving process if they get guidance (i.e. simple rules and instructions). Finally, this study discusses implications for developing information systems to automate and assist the recognition and solving of problems. Such information systems may raise not only the attention of heat pump owners but also trigger desired actions (i.e. request consultancy, inspect heat pump themselves).

Determining the heat transfer coefficient of sustainable buildings using extreme learning machine

In an attempt to eliminate the performance gap in buildings, recent studies have demonstrated the value of on-site heat loss measurements. However, it is recognized that its measurement setup and calculating processes are difficult and complicated. Heat loss via party walls to the outdoors (as opposed to the neighboring dwelling) has drawn a lot of attention, and the building regulations failed to adequately address this issue. In the jamb sections where window frames meet the wall, there is a significant loss of heat. The heat conduction matrix analysis was done using an extreme learning machine (ELM). The main objective for the heat transfer design may be created by a quick and accurate prediction of the building's energy usage during the early design stage. Due to its speed, accuracy, and ability to handle nonlinear variables, ELM is the most popular artificial intelligence model for optimizing building performance. In this study, an approach for predicting building heat loss was developed to simplify building shapes early in the design process and figure out the heat loss ratio. Regarding the regression indices analysis (R2 = 0.879, RMSE = 0.633, r = 0.743), ELM could prove itself as a reliable model in this analysis. In terms of average absolute variation values, ELM demonstrated the highest level of accuracy (85.08 %). Furthermore, ELM required 0.125 s of CPU time to achieve a testing root mean square error (RMSE) of 0:0094, whereas the BP algorithm required 21.21 s of CPU time to achieve a much higher testing error of 0.0151. When compared to the traditional BP models, the new ELM operates 175 times faster. For the wall-foundation system and the slab-on-ground structure, the findings of the heat flux and heat flow acquired using dependable models are 4.3 % and 6.1 % and 10.3 % and 10.7 %, respectively, higher than those obtained using base models. As a consequence, there was a significant difference between the entire house heat loss coefficients that were projected and observed. It was revealed that the bypassing of the thermal insulation through the uninsulated party wall spaces was the most probable reason for the difference.

First report on onsite temperature based recovery of quenched chemiluminescence signal from graphenized μPADs: validation by catechins radical scavenging

Graphene-based materials are excellent acceptors of the CRET phenomenon. Due to the presence of -conjugated planar structure, these materials were reported to quench the chemiluminescence (CL) signal. Based on this fact, herein, for the first time, the recovery of quenched CL signal from different graphene-based materials is successfully obtained through the catalytic activity of onsite temperature. The maximum recovery of a quenched signal at an optimum temperature of 70 was 1440% from the 10 mg ml−1 reduced graphene oxide paper analytical devices. The recovery of flash graphene and laser induced graphene materials were found to be 895% and 521%, respectively, for the same conditions via the generation of -conjugated carbon radicals. Catechin, an antioxidant, was analyzed from 0.1 nM to 500 nM to interpret the generation of carbon radicals from graphenized materials. The proposed smartphone-enabled onsite heating recovery model was validated with the lower limit of 94 pM (27.3 pg ml−1) of catechin concentration without advanced photodiodes or instrumentation. The validation was performed in real samples of green tea (1 and 2). This method of CL recovery can be a future model for indicating the purity of graphene-based materials without using advanced instrumentations.

Framework for the Automated Identification of Possible District Heating Separations to Utilise Present Heat Sources Based on Existing Network Topology

The ambitious climate targets of the European Union emphasise the necessity to reduce carbon dioxide emissions in the building sector. Therefore, various sustainable heat sources should be used in existing district heating systems to cover the heat demands of buildings. However, integrating on-site heat sources into large existing district heating networks could be challenging due to temperature or capacity limitations since such large district heating systems are often supplied by large fossil-based heating plants. Most sustainable heat sources that should be utilised in district heating systems differ in their geographical locations or have limited heat capacities and, therefore, cannot easily replace conventional heating plants. The resulting difficulty of integrating limited heat sources into large district heating networks could be tackled by separating the existing network structure into two independent heat distribution networks. In this study, we present a developed framework that automatically recommends which network parts of an existing district heating system could be hydraulically separated in order to utilise a present heat source that is not yet in use. In this way, a second, standalone district heating system, supplied by the utilised heat source, could be established. The framework applies a community detection algorithm to the existing district heating network to first identify communities in the structure. Neighbouring communities are aggregated to larger network areas, taking into account that these areas could be supplied with the available amount of heat. These network areas are classified as possible areas for separation if the shortest connection path to the utilised heat source is within a certain distance. Subsequently, the found possibilities for network separation are simulated to test a feasible district heating operation and to evaluate the environmental and economic impacts. The presented framework is tested with a meshed and a spanning-tree network structure. Overall, the developed framework presents an approach to utilise present heat sources in separated network structures by automatically identifying, testing and evaluating possible network separations.

System modelling and optimization of a low temperature local hybrid energy system based on solar energy for a residential district

Utilizing solar energy for heat supply can reduce CO2 emissions and mitigate global climate change. In the Nordic region (e.g., Iceland and Finland), a tremendous seasonal mismatch exists between the availability of solar radiation and building heating demand. This paper proposes a local hybrid energy system based on solar energy for a residential district. It applies a borehole thermal energy storage to store solar energy in non-heating seasons, and uses stored energy for part of total heating demand in a residential neighbourhood in heating seasons. Photovoltaic panels are used to generate electricity for heat pump operation. To find out cost-optimal and eco-friendly solutions, the local energy system was first modelled and simulated in TRNSYS. Then, genetic algorithms were applied to optimize the system performance and costs. In optimal solutions, 38%-58% of total heating demand could be covered by on-site heat energy with the levelized cost of energy of 110–184 €/MWh. On this basis, importing additional electricity from grid to increase the utilization rate of air-to-water heat pumps can further increase the on-site heat energy fraction to 41%-88% with the levelized cost of energy of 108–201 €/MWh. Compared with the situation of fully district heating input, the proposed system can annually reduce CO2 emissions by 102–217 tons with the rate of 31–66%. Although the initial cost of the studied system is higher than that of district heating, the local hybrid energy system is worth further developing considering decentralizing heat energy production and reducing CO2 emissions.

A method for assessing heat losses in developing countries with a focus on operational data of a district heating (DH) system

The goal hereof was to propose a new method to estimate heat loss rates and find out how either the weather conditions of the serviced area or the available operational data affect each of the heat loss rate components. A linear regression function was used to describe the correlation between heat production and outdoor temperatures. Monthly measurements are used to estimate onsite heat loss in pipes in Russia. However, model coefficients can be adjusted to make it applicable to any European city, and the simulated behavior of the system is realistic in terms of the temperature profiles and heat losses for any DH system. The proposed model is more accurate than the conventional method with respect to the heat loss difference attributable to the variance in outdoor, supply, return, and ground soil temperatures. The difference between actual heat losses and heat losses projected by this new method varies from 0.4% to 1.2% with an average error of 0.65%. The results also show how the measurements state-of-the-art DH systems provide can help improve daily operation and maintenance to promote data-driven approaches. Technologies can be combined to further improve the performance.

Reinforced catalytic oxidation of polyoxometalate@charge transfer complex by on-site heating from photothermal conversion

Near infrared (NIR) absorption at low energy region has been demonstrated to devoted to photothermal conversion efficiently. This process provides a possibility for valuable extension in emerging photothermal catalysis following a specific approach of molecular composition. To exploit novel photothermal materials in increasing the catalytic activity of comment catalysts, a typical yet unnoticed charge transfer (CT) complex of 3,3′,5,5′-tetramethylbenzidine (TMBCT) is used here as an on-site heater. Through the electrostatic complexation of cationic CT complex bearing strong NIR absorption with series polyanionic clusters, composite catalysts are prepared. These nano-assembled catalysts in size of 5–10 nm display integrated NIR photothermal effect and highly enhanced catalysis for the mild oxidation of toluene and its derivatives into corresponding alcohols with high conversion and selection. While NIR photothermal stability of TMBCT is maintained, the catalytic activity of inorganic clusters is largely improved. The increments in conversion unattainable under external heating condition are realized and the extension to the mild oxidation of thioethers and olefins into sulfoxides and epoxides with acceptable catalytic recyclability and structural stability are demonstrated. All results from the detailed characterizations figure out the applicability of the NIR photothermal conversion to the catalytic reactions with similar catalytic centers.

Factors influencing hydrogen peroxide decomposition dynamics for thermochemical treatment of bottomhole zone

Recently, interest in on-site heat generation has increased due to injection of thermochemical fluids as a complex effect on well productivity. The method of thermochemical treatment with H2O2 while restoring and increasing the filtration characteristics of the bottomhole formation zone is a relatively new and insufficiently studied technology. The article discusses the key factors affecting the exothermic decomposition of this fluid when this fluid is injected into the well. The heat effects, pressure growth and decomposition time of H2O2 were determined depending on the salinity of the water, the composition of terrigenous rock, and various concentrations of H2O2. Physical 1-D modeling of H2O2 injection was carried out on rock models with mobile and stationary oil, which demonstrated a sharp increase in temperature by 100–240 °C caused by the decomposition of H2O2 due to the catalyst and the presence of catalytic active sites in the rock. As a result of this thermochemical treatment, the rock was partially cleaned of immobile oil and heavy sediments. Injection of H2O2 with a catalyst has shown the effectiveness of displacement of mobile oil from the filled sand model. Thus, the results of this study can provide a preliminary assessment of the effectiveness of H2O2 thermochemical treatment in fields operated at a later stage of development.

Decentral Hydrogen

This concept study extends the power-to-gas approach to small combined heat and power devices in buildings that alternately operate fuel cells and electrolysis. While the heat is used to replace existing fossil heaters on-site, the power is either fed into the grid or consumed via heat-coupled electrolysis to balance the grid power at the nearest grid node. In detail, the power demand of Germany is simulated as a snapshot for 2030 with 100% renewable sourcing. The standard load profile is supplemented with additional loads from 100% electric heat pumps, 100% electric cars, and a fully electrified industry. The renewable power is then scaled up to match this demand with historic hourly yield data from 2018/2019. An optimal mix of photovoltaics, wind, biomass and hydropower is calculated in respect to estimated costs in 2030. Hydrogen has recently entered a large number of national energy roadmaps worldwide. However, most of them address the demands of heavy industry and heavy transport, which are more difficult to electrify. Hydrogen is understood to be a substitute for fossil fuels, which would be continuously imported from non-industrialized countries. This paper focuses on hydrogen as a storage technology in an all-electric system. The target is to model the most cost-effective end-to-end use of local renewable energies, including excess hydrogen for the industry. The on-site heat coupling will be the principal argument for decentralisation. Essentially, it flattens the future peak from massive usage of electric heat pumps during cold periods. However, transition speed will either push the industry or the prosumer approach in front. Batteries are tried out as supplementary components for short-term storage, due to their higher round trip efficiencies. Switching the gas net to hydrogen is considered as an alternative to overcome the slow power grid expansions. Further decentral measures are examined in respect to system costs.

A case study comparison of a sulphuric acid plant with and without on-site low-grade heat recovery and repurposing

A case study comparison of a sulphuric acid plant with and without on-site low-grade heat recovery and repurposing

Microfluidic paper device with on-site heating to produce reactive peroxide species for enhanced smartphone enabled chemiluminescence signal

Chemiluminescence signal amplification (CLSA) is of huge interest because of its sensitive detection in various applications such as food analysis, biomedical diagnosis and environmental monitoring. Due to this, there is a manifold attention to develop rapidly prototyped and miniaturized devices for CLSA. In this context, herein, a novel CLSA approach is demonstrated on a 3D printed microfluidic paper-based analytical device (μPADs), fabricated using Fused deposition modeling (FDM) printing technology. Influence of working temperature, ranging 30 °C–110 °C, on CL signal generation from well-established Luminol/Co+2 – H2O2 reaction was analyzed using a screen-printed flexible heater onto the 3D printed reaction platform. A smartphone-based capturing/detection system provided the amenability for a point-of-care testing system. For the first time, strong and stable CLSA was found with about 255% ± 5% increase in its signal intensity without using any additional external enhancers. The on-site working temperature was directly in proportional to the intensity of CL signal generated from Luminol/Co+2 – H2O2 reaction under optimum conditions, wherein the device had a wide linear range from 50 nM to 1 μM with a detection limit of 35 nM for H2O2 detection. The reliability of the developed amplification method was tested for practicability to detect the concentration of H2O2 in milk as real sample analysis. Overall, such CLSA mechanism in miniaturized μPADs will have strong potential for multiple CL based detection and monitoring application.

Bottled Biogas—An Opportunity for Clean Cooking in Ghana and Uganda

Anaerobic digestion (AD) can bring benefits in terms of effective management of organic waste, recovery of nutrients and energy recovery, and is consistent with circular economy principles. AD has been promoted and implemented worldwide, but at widely differing scales, influenced by the availability and location of feedstocks. In developing countries, feedstock arises from small- to medium-scale agriculture and agro-processing operations, as well as from household and municipal waste. Biogas produced from residues from agro-processing facilities may be used for on-site heat and power, but the lack of a gas and electricity grid infrastructure can limit opportunities to distribute gas or generated electricity to wider users. This paper presents the findings of the first study to consider novel technologies for small-scale and low-cost biogas clean-up into biomethane, and compression into small bottles, suitable as a clean cooking fuel. The paper reports on the initial evaluation of biomethane for cooking in Ghana and Uganda.

Energy efficient optimization of heat supply system for oil therminal

In the context of the need to develop the transport infrastructure of Ukraine and to diversify sources of energy carriers supply to the country, including oil and oil products, the problem of the development of oil terminals arises. This work is devoted to the optimization of the structure of heat supply to oil terminals. In this sense it is relevant. The object of research is the heat supply systems of an oil terminal. At the same time, the subject of research is the energy efficiency of heat supply systems for oil terminals using water vapor and high-temperature organic heat carriers. The following research methods were used: an analytical review of information sources, a technical and economic analysis with the necessary substantiating calculations. As a result of the studies, the possibility of using high-temperature organic heat carriers for organizing heat supply to oil terminals has been shown. The advantage in the efficiency, environmental friendliness and reliability of systems with high-temperature organic heat carriers versus systems using water vapor as a heat carrier is shown. On-site heating networks in the oil terminal are recommended. The main advantages are that the heat losses in them have been reduced and the reliability of the system has increased. The cost estimation of capital investments of the compared variants of the heat supply system arrangement is carried out. The centralized heat supply systems have greater equipment cost compared with the decentralized ones. The operating cost for decentralized systems is also lower due to a decrease in specific fuel and electricity consumption. The materials obtained as a result of the research can be used as recommendations for the design of heat supply systems for oil terminals using high-temperature organic heat carriers.

On-site measurement of heat of hydration of delivered mass concrete

In this study, measurements of the heat of hydration of mass concrete delivered on-site were proposed. A one-meter concrete cube, cast adjacent to the real structure, was developed as an on-site semi-adiabatic calorimeter. A table was established for the required insulation of the cube in different ambient temperatures. To simplify the measurement process and cost, a method was developed to obtain the concrete adiabatic temperature rise (ATR) by simply using the measured temperature at the center of the cube. The finite element method (FEM) was used to calculate the required insulation for various ambient conditions between −10 to 30 °C so that the ATR could be accurately estimated using only the measured center temperature. The predicted ATR and the actual ATR showed less than 1% error. The proposed heat of hydration measurement was tested during four on-site field castings at three different districts in West Virginia. Two of the field batches contained 50% Grade 100 ground granulated blast furnace slag replacements. The fourth field batch had 30% Class F fly ash replacement. The material collected from each field test was also used to perform laboratory adiabatic and isothermal heat of hydration measurements. The ATR calculated from the on-site cube data compared well with the results from both adiabatic and isothermal calorimetry tests. The heat of hydration parameters were successfully obtained based on the ATR calculated from each on-site casting. Results show that the proposed on-site heat measurement can be a simple and accurate approach to measure the heat of hydration of a delivered concrete batch.