Reactor Heat Research Articles

Kinetic parameters underlying hematite-assisted decomposition of tribromophenol

Interaction of brominated flame retardants (BFRs) and transition metal oxides is a widely utilized approach in thermal recycling of bromine-contaminated plastics. An optimum design of the operation requires the development of accurate thermo-kinetic parameters that dictate the co-degradation of both entities. To attain this obviative, thermal degradation behavior pertinent to co-pyrolysis and co-combustion of hematite (Fe2O3): tribromophenol (TBP) mixtures was explored in a thermogravimetric analyzer (TGA) at various heating rates. Thermo-kinetic parameters for mixtures were acquired based on TGA runs while employing three major model-free or isoconversional methods (KAS, Starink, and FWO) and model-fitting methods (Coats-Redfern). Obtained profiles infer that the addition of hematite systematically reduces the governing activation energy (Ea) in both thermochemical processes in reference to neat TBP. The hematite-assisted debromination of TBP under oxidative conditions entails lower activation energy when compared with degradation under pyrolytic conditions. Molecular modeling mapped out initial mechanisms that operate in the interaction with a prime focus on reactions that lead to ring opening of the aromatic rings. Overall, the results obtained from the thermal chemical conversions find direct application in reactor modeling and heat transfer design in domains related to the recycling of electronic and electrical waste (e-wastes).

Miniature glass-metal coaxial waveguide reactors for microwave-assisted liquid heating

<abstract> <p>Microwave (MW) irradiation is recognized as an effective tool in industries related to pharmaceuticals, chemistry, nanoparticle synthesis, food, etc. In the hardware field, some research efforts are concentrated on creating miniature reactors using low-cost technologies aimed at on-demand chemistry or parallel synthesis of many drugs.</p> <p>This paper reports on the development and characterization of novel miniature chemical-resistant glass-metal coaxial reactors based on a modified Liebig condenser. It is composed of two concentric glass tubes, one for the central conductor carrying MW current, and the other for the copper-foiled cylinder surrounding the first pipe. The gap between them is filled with a liquid that is pumped and evacuated by using shielded thin inlet/outlet glass tubes, which are melted and opened into this cylindrical cavity. The reactor's geometry allows for the direct soldering of miniature MW SMA coaxial connectors of 50-Ω impedance.</p> <p>The developed components are studied analytically, numerically and experimentally. The frequency properties of reactors are measured with a network analyzer. The temperature trends are explored by using a variable high-power MW generator, power meters and temperature sensors.</p> <p>These reactors demonstrate their relative insensitivity toward variations in the permittivity of filling liquids in the range of $3.75 < \varepsilon < 30$, as shown in simulations and measurements. They demonstrate the increase by two orders in the longitudinal modal penetration depth and a more homogeneous heating along reactors as compared to their hollow coaxial prototypes.</p> <p>These glass-metal miniature reactors can be used in on-demand continuous-flow accelerated liquid heating, chemistry and pharmacy.</p> </abstract>

Исследование влияния качества поверхности при изготовлении комбинированных теплообменных элементов технологических реакторов путем склеивания

As is known, the problem of durability is directly related to the technological processes of manufacturing reactor elements, including elements in contact with the internal reactor environment – the reaction zone. Based on this, it is important to develop new, as well as modernize old technologies for manufacturing reactor equipment elements in order to improve their technical and operational characteristics. The technology developed by the authors of this manuscript can act as a technology for manufacturing and assembling elements of reactor equipment. This technology consists of several main stages. One of these stages is the process of roughness formation on the contacting surfaces before gluing them. However, it is necessary to understand that different values of roughness indicators lead to a change in the strength characteristics of adhesive joints. In view of this, the purpose of this study is to determine the strength characteristics of the adhesive joint at various Ra values and adhesive temperature. The article presents an analysis of the most popular thermochemical reactors at the present time, as well as an analysis of the main types of malfunctions leading to the failure of reactor equipment. The developed manufacturing technology of the most wear-prone parts of the reactor (heat pipes, shells) is described. A feature of this technology is the possibility of forming a thermal contact surface on the manufactured parts, which acts as an intensifier of heat exchange, increasing the efficiency of the unit. The practice of using high-strength and high-temperature adhesives is analyzed. Studies have been carried out to determine the strength of adhesive compounds under various conditions. Heat–resistant epoxy adhesives of K-800 and CMK-Vt brands were used as adhesive compositions. The influence of the Ra index in the range from 1 to 6 microns and the influence of temperature in the range from 200 to 600°C on the strength of the adhesive seam is shown.

Nickel-palladium bimetallic nanoparticles supported on multi-walled carbon nanotubes; versatile catalyst for Sonogashira cross-coupling reactions.

We have developed an efficient method to generate highly active nickel-palladium bimetallic nanoparticles supported on multi-walled carbon nanotubes (Ni-Pd/MWCNTs) by dry mixing of the nickel and palladium salts utilizing the mechanical energy of a ball-mill. These nanoparticles were successfully employed in Sonogashira cross-coupling reactions with a wide array of functionalized aryl halides and terminal alkynes under ligand and copper free conditions using a Monowave 50 heating reactor. Notably, the concentration of palladium can be lowered to a minimum amount of 0.81% and replaced by more abundant and less expensive nickel nanoparticles while effectively catalyzing the reaction. The remarkable reactivity of the Ni-Pd/MWCNTs catalyst toward Sonogashira cross-coupling reactions is attributed to the high degree of the dispersion of Ni-Pd nanoparticles with small particle size of 5-10 nm due to an efficient grinding method. The catalyst was easily removed from the reaction mixture by centrifugation and reused several times with minimal loss of catalytic activity. Furthermore, the concentration of catalyst in Sonogashira reactions can be reduced to a minimum amount of 0.01 mol% while still providing a high conversion of the Sonogashira product with a remarkable turnover number (TON) of 7200 and turnover frequency (TOF) of 21 600 h-1. The catalyst was fully characterized by a variety of spectroscopic techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).

Optimal retrofit of a novel multi-component supercritical thermal fluid generation system via thermodynamic analysis

• A novel thermal fluid generation system is first developed, introduced and modelled. • Sensitivity analysis of three key single factors and their combinations are performed. • Reactor and heat exchanger are the bottleneck units to overall efficiency improvement. • An optimal retrofit design with around 10% efficiency increased are proposed. Multi-component supercritical thermal fluid (mcSCTF) has been recently recognized as a promising media for enhancing heavy oil recovery. For its economic application, an efficient mcSCTF generation should be studied. In this work, a novel experimental system with various units is being first introduced for mcSCTF generation and theoretically modelled for the energy and exergy analysis as the two contributions of this work. Based on the results, optimal retrofit strategy is proposed as the coming improvement. Starting with a specific experimental setup, theoretical modeling methods including Gibbs free energy minimization and mass balances are employed to predict the output of the core unit of reactor. The models are validated using measured experimental data. Then, energy and exergy analysis are conducted to quantify the energy and exergy losses in each unit. The reactor, heat exchanger and compressor are found to contribute for the major exergy losses accounting for 40.1%, 39.4% and 12.3%, respectively. With this, sensitivity analysis of three key factors (i.e., reactor heat dissipation rate, heat exchanger efficiency, and compressor isentropic efficiency) as well as their combinations are performed to identify potential solutions for improving efficiency. Finally, a retrofit design with around 10% efficiency enhancement is proposed.

Production, Characterization and Evaluation of Pyrolysis Oil from Tyre Wastes Available in Bangladesh

Globally, scrap tyres are increasing due to the increased number of vehicles. In contrast, in the recent years, alternatives to fossil fuels are exploring to overcome the fossil fuel crisis. In this study, pyrolysis of bicycle and rickshaw tyres wastes was conducted and parametric effects (e.g., the effect of temperature, feed size and apparent vapor residence time etc.) on the pyrolysis product yields were determined. A fixed bed electric heating reactor was used for pyrolysis at 400 - 550 oC, maintaining various particles sizes and a constant heating rate of 20oC/min. The optimum Tyre Pyrolysis Oil (TPO) yield of 42 wt.% was obtained at 500 oC for a sample size of 4.0 cm3. The fuel properties (e.g., density, viscosity, calorific value, flash point, pour point, sulphur content, ash content etc.), functional group studies of the TPO were determined and was compared with the conventional fuel and with international standards. The physico-chemical properties of TPO confirm the use of TPO as furnace oil in various industrial processes. The fractionation of bio-oil gives various value added products including bio-gasoline, bio-kerosene and others chemicals. The commercial implementation of the pyrolysis and follow-up technologies for waste tires processing will allow energetic valorization of waste tyres in Bangladesh. Dhaka Univ. J. Sci. 70(2): 29-34, 2022 (July)

Pyrolyzing coal blended with ash: The fate and impacts of CaSO4

Pyrolysis of Xiaolongtan lignite with and without CaSO4-containing coal ash premixed is performed at 500–850 °C in an infrared heating reactor to clarify the fateful roles of CaSO4 in causing effects of ash on pyrolysis. The presence of coal ash rich in CaSO4 significantly raises the yields of CO2, pyrolysis gas and water but decreases the H2 yield at temperatures above 750 °C. Analysis of the ash after pyrolysis clarifies that CaSO4 is mainly reduced to CaS at those temperatures, and other ash components such as Fe2O3 change little. Similar decreases in H2 and CO and increases in CO2 and water are also identified in testing the reactions between simulating pyrolytic gas and coal ash, and the mechanism is thought to be 4 H2 + CaSO4 → CaS + 4 H2O and 4CO + CaSO4 → CaS + 4CO2. Studying the reactions between char and ash further elucidates that carbon is oxidized by CaSO4 to form CO2 through C + CaSO4 → CaS + 2CO2.

Modelling of an interacting series process for rector cooling system using system identification method

This research presents the modelling of cooling system plant in the TRIGA PUSPATI reactor (RTP). The RTP cooling system involves the interacting series process which are reactor model and heat exchanger model. The behaviour process is complex due to the nonlinearity, uncertainty, and time variation of the system. Due to the nonlinearity and interacting series process of system, the numerical algorithm for subspace state space system identification (N4SID) was proposed in the modelling of RTP cooling system. However, the model was converted to the transfer function form. The output response from the simulation model of RTP cooling subsystems were analysed by comparing the model with the real operational data. The responses of the model were within the respective range of a good model data. The residual analysis for each output was also calculated. The comparison and residual analysis were done to validate the model accuracy to determine the behaviour of the model. Overall, the model accuracy assessment shows that all models are still fit in the good model region (<10%) and has a good representation of a real plant.

Heat Transfer on Micro and Nanostructured Rough Surfaces Synthesized by Plasma

The review summarizes recent experimental results of studying heat transfer on rough surfaces synthesized by plasma. The plasma-surface interaction leads to the stochastic clustering of the surface roughness with a high specific area breaking the symmetry of the virgin surface of the initial crystalline materials. Such a surface is qualitatively different from the ordinary Brownian surface. The micro- and nanostructured surface consist of pores, craters, and nanofibers of size from tens of nanometers to tens of microns, which can provide new heat transfer properties related to a violation of the symmetry of the initial materials. In recent years, new results have been obtained in the study of heat transfer during phase change on plasma-modified surfaces in relation to energy, chemical, and cryogenic technologies. The objective of the review is to describe the specific structure of refractory metals after high-temperature plasma irradiation and the potential application of plasma processing of materials in order to create heat exchange surfaces that provide a significant intensification of two-phase heat transfer. Refractory metals with such a highly porous rough surface can be used as plasma-facing components for operation under extreme heat and plasma loads in thermonuclear and nuclear reactors, as catalysts for hydrogen production, as well as in biotechnology and biomedical applications.

Experimental Study on Singlephase Natural Circulation Flow and Heat Transfer of Passive Residual Heat Removal System of Swimming Pool-type Low-temperature Heating Reactor

Experimental Study on Singlephase Natural Circulation Flow and Heat Transfer of Passive Residual Heat Removal System of Swimming Pool-type Low-temperature Heating Reactor

On the Elucidation of Polymer Fouling Mechanisms and Ethylene Decomposition in High‐Pressure LDPE Tubular Reactors

AbstractIn high‐pressure free‐radical ethylene polymerization tubular reactors, fouling often occurs due to polymer deposition onto the reactor's wall surface. This results in a decrease in the overall heat transfer coefficient. Note that a high‐pressure tubular reactor must be capable of removing about half of the generated polymerization heat to the cooling water flowing into the reactor's jackets. Therefore, reactor fouling can have serious implications including decrease of heat removal rate and monomer conversion, increase in the overall initiator(s) consumption, change of polymer quality, decline of reactor's safe operation, and significant economic losses due to lower plant productivity and longer reactor maintenance periods. In rare cases, the loss of reactor's heat removal capacity may result in the appearance of local hot spots that eventually can trigger ethylene decomposition. In the present review paper, the fundamental physical and chemical phenomena regarding polymer fouling and ethylene decomposition in high‐pressure low density polyethylene (LDPE) reactors are critically discussed. The effects of shear rate, polymer molecular weight, and wall surface energy on polymer adsorption and desorption are analyzed. Moreover, the effect of characteristic initiator decomposition and micromixing times and process conditions on initiator dispersion, polymer fouling, and ethylene decomposition are assessed.

The vibrational and dielectric properties of diamond with N impurities: First principles study

The atomic and electronic structures as well as elastic and dielectric properties (including first simulations of loss tangent, tan δ) of diamond with nitrogen impurities are calculated using the first principles LCAO method and the hybrid functional B3LYP. The effect of the single nitrogen substitutional atom (C-center) on the Raman and IR absorbance spectra is analyzed and compared with other calculations. It is shown that nitrogen defects do not affect tan δ at far IR region used in diamond windows in fusion reactors for plasma heating and stabilization.

β decay of Ba141

The $\ensuremath{\beta}$-decay strength function of nuclides produced in fission is important as it dictates the distribution of decay energy between electrons, neutrinos, and $\ensuremath{\gamma}$ rays and so is critical for calculating decay heat in reactors and for estimating the reactor antineutrino spectrum. Several experimental techniques are available to determine this strength function, including electron spectroscopy, $\ensuremath{\gamma}$-ray calorimetry (TAGS spectroscopy), and detailed, high-resolution spectroscopy with modern large high-purity germanium arrays. This work investigates the decay of the well-known and strongly produced fission fragment $^{141}\mathrm{Ba}$. A beam of $^{141}\mathrm{Cs}$ was implanted at the target position of the Gammasphere and the subsequent decay of the daughter $^{141}\mathrm{Ba}$ was studied. Extensive decay spectroscopy was possible up to the decay $Q$ value of 3.197(7) MeV, including a significant extension of the level scheme and detailed angular correlation measurements for all levels with greater than $0.25%\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$ feeding. The distribution of the $\ensuremath{\beta}$-decay strength was then inferred and compared to previous calorimetric studies. The agreement was excellent and provides a benchmark for comparing strength function methods and data for a more detailed understanding of the structure of $^{141}\mathrm{La}$.

A Feasibility Study of Utilizing Nuclear Energy for an Existing MED-TVC Desalination Plant

This study aims to investigate the viability of using a nuclear heating reactor to supply energy and replace the used fossil crude oil energy supply of an existing MED-TVC (Multi-Effect Distillation-Thermal-Vapor-Compression) desalination plant located in Saudi Arabia. The MED-TVC, with a 91,200 m3/day capacity, was simulated using Aspen Plus®. The MED-TVC desalination plant was built in a parallel arrangement with oil-fired steam boilers, and it uses Red Sea water with a salinity of about 45,000 ppm. The simulation results of the MED-TVC are in good agreement with the actual data of the existing desalination plant. The heat required to operate the existing MED-TVC was determined to be 169 MW (th). This amount of heat was utilized as an input to DEEP (Desalination Economic Evaluation Program) to evaluate the production cost of fresh water using nuclear energy instead of fossil fuel. An economic comparison between the two energy sources was carried out in this study. The production cost of freshwater was estimated to be USD 1.38/m3 when using a nuclear reactor. In contrast, the estimated production cost was USD 0.95/m3 when using oil-fired boilers at a subsidized oil price of USD 4.4/bbl. The economic analysis has considered the discounted domestic crude oil prices in Saudi Arabia. Nuclear energy is cost-competitive with oil if Saudi Arabia raises the price of domestic crude oil to more than USD 15 per barrel or imposes a carbon tax of at least USD 20 per ton of greenhouse gas emissions.

THE PROBLEM OF HYDROGEN, HYDROGEN AND ATOMIC-HYDROGEN ENERGY: PHYSICAL, CHEMICAL AND TECHNOLOGICAL ASPECTS, TECHNICAL AND ECONOMIC ANALYSIS (REVIEW)

The review attempts to systematically and analytically consider certain results of scientific research and applied developments of such an urgent problem of our time as «hydrogen, hydrogen and atomic hydrogen energy» over the past 15–20 years. In the context of a reasoned statement of the problem, the main categorical-conceptual apparatus of the problem is determined. The main directions and issues of research on the phased solution of the problem are indicated. It is proved that the foundation of the problem is the understanding of the physicochemical properties of hydrogen as a chemical element and its characteristics as a simple substance based on a number of its specific properties. The phenomenon of hydrogen corrosion and its analysis from the point of view of the level of danger, the risk of its use and safety precautions are considered. Attention is focused on the features of the processes of storage, transportation and use of hydrogen as an energy carrier and raw material for technologies. The advantages of obtaining and using solid-phase hydrogen compounds with metals and intermetallic compounds as convenient and safe means of hydrogen transfer to consumers are noted. An example of the use of the most effective hydrides as carriers of H2 in motor vehicles by adding H2 to the minfuel in the engine power system is given, illustrated by a diagram. Special conditions for the use of H2 in heat supply processes (in thermal power engineering in general) are indicated, taking into account the difference in the thermophysical characteristics of H2, CH4, air and oxygen. The features of the development and use of means of transportation and storage of H2 are noted. Considerable attention is paid to the consideration of the physicochemical foundations for the production and use of metal hydrides and intermetallides in the context of evaluating them as means of solid-phase storage of H2 transfer in technological processes. The classification of hydrides and their functional characteristics of the most effective and promising hydrides — metal-like and especially intermetallic ones are presented: their preparation and areas of use. The innovative concept of atomic hydrogen energy is described in detail, which will determine the most promising areas of practical developments on the subject of the problem and their implementation. The concept is based on the use of the heat of a gas-cooled nuclear reactor for the implementation of two types of tasks: the efficient use of hydrogen as an energy carrier, for example, in the field of heat supply; the efficiency and profitability of methods for producing hydrogen using the numerous methods, methods and technologies already proposed, which, without nuclear technologies, are currently low-efficient and unprofitable. A project is proposed for using the heat of a GOx-th nuclear reactor in a fundamentally new complex of distant heat supply (method, technology, schemes) using a two-stage, reversible chemo-thermal process. It has been proven that the heat of a nuclear reactor can be used for the effective implementation of a number of traditional and innovative chemical and electrochemical, biochemical, etc. reactions for obtaining H2. A feasibility study has proven the effectiveness of such nuclear-hydrogen energy. A complete list and analysis of innovative, reversible (cyclic) chemical reactions for the production of H2 is presented. The review is based on the latest references to foreign publications on the subject of the problem (2018–2022), obtained from such an international source as «Elsevier-Science Direct». Bibl. 26, Fig. 4, Tab. 5.

Improving catalyst performance of Ni-CaO-C to enhance H2 production from biomass steam gasification through induction heating technology

Catalyst performance plays a key role in biomass gasification for H2 production. In this study, induction heating technology was proposed to in-situ heat Ni-based catalyst via Joule heating effect to improve the catalyst performance during steam gasification of biomass for enhancing H2 production. Scanning electron microscope, Brunauer-Emmett-Teller, Thermogravimetric analysis and X-ray diffraction analysis confirmed that less coke deposition, larger specific surface area and more active sites of Ni particles with better crystallinity degree were observed for the used Ni-CaO-C catalysts in induction heating reactor compared to conventional heating reactor (Electric resistance heating). Thus, Ni-CaO-C catalyst in induction heating reactor showed significantly higher catalyst performance, and the H2 production was greatly enhanced from 591–692 mL/g-biomass to 1097–1325 mL/g-biomass (increase rate up to 101.1 %). Furthermore, adding metallic particles into catalyst bed in induction heating reactor can also promote the catalyst performance and then enhanced H2 production. By using induction heating catalytic technology coupled with metallic particles addition, all the H2 yields from steam gasification of four typical biomass (reed straw, wheat straw, corn cob and rice husk) were increased (increase rates reached 106.6–133.5 %) compared to conventional heating reactor. And the ranking of the positive effects of Ni and metallic particles via induction heating on enhancing H2 production was as follows: Ni + Metallic particles coupling effect > Ni effect > Metallic particles effect. Under the optimal conditions, the H2 yields from these four biomass were as high as 1803, 1805, 1722 and 1740 mL/g-biomass, respectively.

Greener approach for the synthesis of nitrovinylfurans from biomass-derived 5-hydroxymethyfurfural as selective antiproliferative agents

Biomass-derived chemical platforms such as 5-hydroxymethylfurfural (5-HMF) can offer straightforward access to new value-added products. The presence of an aldehyde and hydroxymethyl functional groups in this molecule are interesting structural motifs to explore the synthesis of new bioactive compounds. In this contribution, a strategy to quickly and efficiently synthesize nitrovinylfurans starting from 5-HMF under greener conditions is described and the antiproliferative activity of the synthesized compounds evaluated. 5-HMF obtained by microwave-assisted saturated biphasic dehydration from fructose was used to produce furaldehyde derivatives. Next, through a nitroaldolic condensation, the desired nitrovinylfurans were generated using efficient heating sources, ultrasound, or a non-microwave instant heating reactor, under solvent-free conditions. Most of the newly synthesized compounds showed growth inhibition when assayed for their in vitro antiproliferative activity against six cancer cell lines (A549, HBL-100, HeLa, SW1573, T-47D, and WiDr), with lower toxicity on the human macrophage-like cells (THP-1). Our strategy allowed the rapid identification of nitrovinylfurans 16, 17, 19, and 20 as future candidates for the development of new selective anticancer drugs.

Hydrogen generation characteristics of reduced DME steam reforming catalysts according to heating methods

The purpose of this study is to investigate the hydrogen generation characteristics of H2-reduced dimethyl ether (DME) steam reforming (SR) catalysts using different heating processes. The effects of the H2 reduction temperature and space velocity were investigated to identify an optimal reaction environment. Both the resistive and induction heating methods were used. The catalysts were prepared by impregnating copper over a γ-Al2O3 support. The Cu/Al2O3 catalysts with different loading amounts of 5–15 wt% Cu exhibited different characteristics when subjected to hydrogen reduction. The variation in acidity had a dominant effect on the DME-SR activity, and 15Cu/Al2O3 that underwent hydrogen reduction treatment at 500 °C attained improved performance at low temperatures and low formation of by-products, allowing for the achievement of its highest H2 concentration of 74.08% at 375 °C. The induction heating reactor had an energy consumption that was about 25% lower than that of the resistive heating reactor.

Heat transfer performance of the solid microencapsulated fuel in light water reactors

Solid Microencapsulated Fuel (SMF) is a kind of new accident-tolerant fuel (ATF) concept that disperses TRISO coated fuel particles directly into a type of matrix in the form of a solid rod. This paper aims to analyze the heat transfer performance of SMF based on a single pin, compared to the traditional fuel design in the 200 MW Nuclear Heating Reactor (NHR200-II). Two kinds of SMFs have been evaluated - fuel particles dispersed into a silicon carbide matrix and fuel particles dispersed into a zirconium matrix. The centerline temperature of the SMF rod at the beginning of life (BOL) was preliminarily calculated based on the effective thermal conductivity (ETC). The ETC was calculated by Maxwell, Chiew&Glandt, and d-EMT models, compared to the finite element models. The ETC of TRISO particle was also calculated before calculating that of the SMF rod because of its multilayer structure. To get a more realistic temperature distribution of SMF rod, a neutronic analysis was done by OpenMC by acquiring the power distribution of randomly distributed TRISO particles. Finally, a practical temperature distribution of SMF rod was achieved by the finite element model considering the random distribution of TRISO particles. This study showed that SMF has a better thermal transfer capacity than conventional fuel design and even fully ceramic microencapsulated (FCM) fuel because of its integral structure and higher matrix thermal conductivity. The helium gap in conventional fuel and FCM fuel would bring a temperature rise of nearly 150˚C in this case. The centerline temperature of SMF is much lower than the traditional fuel. A more refined temperature distribution of SMF rod based on the finite element model showed a lower maximum temperature than the ETC calculated. It also showed a less uniform temperature distribution because of the heat generation of fuel particles and the possible concentration of randomly distributed fuel particles.

Adsorption Solar Air Conditioning System for Singapore Climate

The design of an adsorption solar air conditioning system is investigated by using a model with an activated carbon–methanol working pair. This system is analysed with the solar insolation levels and ambient temperatures of Singapore. The proposed design mainly consists of two tubular reactor heat exchangers (TRHEXs) operating out of phase and driven by heat from an evacuated tube solar collector (ETSC). The pair of TRHEXs act as a thermal compressor and contain about 2.275 kg of activated carbon per reactor. The evacuated tube solar collector (ETSC) has better performance and is more cost effective than the flat plate solar collector (FPSC), even though it has a higher cost per unit. On the hottest day of the year, the proposed adsorption system has a maximum cooling power of 2.6 kW and a COP of 0.43 at a maximum driving temperature of 139 °C with a 9.8 m2 ETSC area. The system has a total estimated cost of EUR 10,550 corresponding to about SGD 14,800 with a 7-year payback time. At similar cooling capacities, the adsorption air conditioning system is expected to be more cost effective than the conventional system beyond an expected period of 7 years, with an expected lifetime of 15 to 20 years.