Circulation Heat Research Articles

Black liquor-based hydrogen and power co-production: Combination of supercritical water gasification and syngas chemical looping

An integrated system to efficiently harvest energy from the waste produced in the pulp mill industry, namely black liquor (BL), is proposed and investigated. The proposed system mainly comprises the supercritical water gasification (SCWG) of BL and syngas chemical looping (SCL). In addition, to effectively minimize the circulation of heat throughout the system, and therefore optimize the energy efficiency, the process design and integration are conducted by simultaneously adopting the concepts of exergy recovery and process integration. The available technologies for electricity generation and hydrogen production from BL recovery are discussed and compared with the proposed system. In this study, hydrogen is set as the main output, while power is produced by utilizing the heat generated throughout the process. Process simulation is performed using a steady state process simulator Aspen Plus. Energy efficiency is classified into three categories: hydrogen production efficiency, power generation efficiency, and total energy efficiency. Compared to other BL recovery systems, the proposed integrated system combining SCWG and SCL processes seems to be very promising. The integrated system shows very high total energy efficiency and carbon capture of about 80% and 75%, respectively.

Integrated system of thermochemical cycle of ammonia, nitrogen production, and power generation

Ammonia (NH3) is one of the most valuable chemicals due to its multipurpose utilization in many applications. Beside major application as fertilizer in agriculture, NH3 is a promising hydrogen (H2) carrier because it has a high content of H2 and technically available storage and transportation systems. At present, most of NH3 is synthesized from a series of steam reforming process to the feedstock of H2 and nitrogen (N2) production, followed with the catalytic Haber-Bosch reaction. In this study, an integrated system of N2 production system, NH3 synthesis system and a power generation process is proposed to produce NH3 efficiently. Thermochemical cyclic process of an endothermic reaction of Al2O3 reduction by carbon in N2 atmosphere, is coupled with oxidation/steam-hydrolysis of aluminum nitride (AlN) back to Al2O3, producing NH3 without catalyst and the need of H2 production system. The thermal energy required for reduction reaction is covered by the heat generated during exothermic reaction and combustion process, and the remaining heat is utilized in power generation. Heat circulation optimization is carried out by applying the enhanced process integration, resulting in a highly efficient system. The proposed system is analyzed through an adjustment of the main parameters: oxidation temperature, steam turbine inlet pressure, and temperature, to observe their effect on system performance and efficiency. The proposed system can reach a very high system efficiency of 69.3%. The oxidation reaction temperature is observed to play major role in determining the system performance due to temperature dependent NH3 yield.

Adiabatic behavior of gas wells due to natural reservoir fines migration: analytical model and CFD study

The adiabatic behavior of natural gas production well is frequently neglected in the reservoir formation damage study. The temperature of surrounding formation contributes to the smooth flow of natural gas in the wellbore. The heat transfer from the formation and geothermal gradient plays vital role in the efficient transport of gas in the subsurface formation and wellbore. But, fine particles which are attached to the rock surface migrate and are trapped in the pore throats, and as a result, there is deterioration in the permeability. The detachment of fines occurs due to high reservoir temperature and gas internal energy and temperature. Therefore, this paper conducts theoretical and numerical investigations on the adiabatic behavior of natural gas production well due to in situ reservoir fines migration. Firstly, an analytical model is developed and then, numerical models were constructed using CFD simulation tool to study the adiabatic nature of a gas well. A total of 24 cases were run in simulation, and input temperatures such as 200 °C, 250 °C, 300 °C, 350 °C, 400 °C and 450 °C were given for modeling. The results revealed that there was no sign of heat transfer from the wellbore to the surroundings. There was a heat circulation only within the wellbore. During the adiabatic state, the pressure in the central zone of the gas well is moderate, but rises linearly on the radial sides.

The use of heat circulator for flammability in mesoscale combustor

The mesoscale combustor is a part of the micropower electric generator. The function of the mesoscale combustor is to convert hydrocarbon to become thermal energy through combustion reaction. It is difficult to maintain the flame stability of a mesoscale combustor due to its millimetre-scale size.This study aims to determine the performance and recognize mesoscale combustor phenomena that have stainless steel heat recirculators. This study is to test the combustion characteristics of liquid and gas fuels in meso-combustors which use heat recirculator. The heat circulator is made of stainless steel tube with an inner diameter of 3.5. The parameters observed were flammability limits, temperature distribution and flame visualization.It is confirmed that the stainless steel heat recirculator, is useful for liquid fuel preheating and evaporating inside of mesoscale combustor. The flame of liquid fuels can be stabilized at an equivalence ratio of 0.9 to 1.25, and up to about 900 centigrade Celsius. Thus recommend for liquid fuel micropower generator. It is noted that when the heat recirculator is too close to the flame, excessive flame cooling occurs and causes the flame extinguished. The meso-combustor, which has no heat recirculator, and designed for gas fuel only, can stabilize flame at an equivalence ratio of 0.7 to 1.5. It is also confirmed that the inaccurate selection of the material of thermal recirculator risks reducing the flame stability. It is important to note that when the gas fuel exits the storage tube, there is an expansion and a decrease in temperature which can affect flammability limits

The Effect of Internal Variability on Ocean Temperature Adjustment in a Low‐Resolution CESM Initial Condition Ensemble

AbstractDue to its large heat capacity and circulation, the ocean contributes significantly to global heat uptake, global heat transport, spatial temperature patterns, and variability. Quantifying ocean heat uptake across different temporal and spatial scales is important to quantify Earth's climate response to anthropogenic warming. Here we evaluate ocean adjustment time scales from two different fully coupled climate model ensembles using the Community Earth System Model. Both ensembles use the same model version, anthropogenic and natural forcings, and coupling configurations, but we initialize the ensembles in two different ways: (1) sampling joint internal variability of the ocean–atmosphere system (unique atmosphere and ocean conditions) and (2) sampling the internal variability of the atmosphere only (unique atmosphere, identical ocean conditions). Uncertainty due to internal variability is used as a proxy to quantify the time scales of ocean temperature adjustment at different depths and basins in Community Earth System Model. Time scales of equilibration are longer in the deep ocean than the upper ocean, highlighting the vertical structure of dynamic adjustment. The Atlantic equilibrates on shorter time scales (82 years above 1,000 m, 140 years below 1,000 m) relative to the Pacific (106 years above 1,000 m, 444 years below 1,000 m) in Community Earth System Model due to the large North Atlantic Deep Water formation and strong overturning circulation in the Atlantic. These results have broad implications for analyzing internal climate variability, ocean adjustment, and drift in global coupled model experiments and intercomparisons.

Numerical investigation of transient natural convection and entropy generation analysis in a porous cavity filled with nanofluid considering nanoparticles sedimentation

In the present study, effect of nanoparticle sedimentation on characteristics of natural convection heat transfer inside a completely porous cavity filled with Al2O3/water nanofluid was investigated over time, and entropy generation was analyzed from the viewpoint of the second law of thermodynamics. In order to simulate this phenomenon using a two-phase mixture model, a new solver was developed in OpenFOAM framework based on driftFluxFoam and buoyantBoussinesqPimpleFoam solvers. Effects of Rayleigh number (Ra=104−107), Darcy number (Da=10−5−10−2) characteristics were further analyzed. Numerical results indicated very long sedimentation time for low porosities and extended cavity lengths. Also, with increasing the values of L, ε, Ra and Da, natural convection heat transfer, circulation, and irreversibility of the process increased significantly. It was further seen that, the Nusselt number decreased during the nanoparticle sedimentation process. Formation of sediment layers at the bottom of the enclosure reduced the streamlines, as compared to the primary streamlines, thereby decreasing natural convection and rotational flow while contributing to conductive heat transfer.

Studies on acoustic comfort in a passive house

Acoustic comfort is a requirement of major importance during the design of houses. This study focused on the acoustic comfort parameter called sound pressure level. The value of this parameter is variable during operation of a particular building , depending on the type of absorbent material and them surface. The aim of this study is to determine the influence of the equipment of the technical space for a passive house . In this study was experimentally determined the value of noise for a Passive House in Romania using specialized equipment and software from Bruel & Kjaer . With these equipment and software were simulated different functional parameters of heat recovery and circulation pump, and different ways of placing the house on various types of roads leading sound pressure level simultaneously for five rooms , result compared with rules imposed values for each type of room.

Experimental study on visualization of U-shaped array thermosyphon

U-shaped array thermosyphon has no capillary core structure, which can be used for power battery thermal management. In this paper, we performed a visualization experiment about U-shaped array thermosyphon. Its fluid flow and heat transfer mechanism and the influencing factors are studied. With input of heat power, the thermosyphon underwent stages of cold start-up, heat energy storage, transition and circulation flow stage. Before the start-up of the thermosyphon, there would be three kinds of vapor-liquid states of the working fluid, namely vapor tube, liquid tube and vapor plug liquid slug tube. After the start-up, the corresponding change were slug flow, annular flow or liquid cylinder oscillation. Slug flow and annular flow relative to liquid cylinder oscillation can enhance heat transfer. The main factors affecting the performance of the U-shaped array thermosyphon are the filling rate and working fluid. The liquid filling rate affects the stage of the working fluid at the stationary state and the flow pattern at the circulation flow state. Taking the temperature difference of start-up and the stability of circulation flow as the evaluation criterion, the performance of the thermosyphon of R134a is better than that of R113.

Features of heat transfer in the environment when it is sprayed with rotary rollers

The analytical analysis of roller impact on the medium and its behaviour at deformation influences are carried out, ways of choosing an optimal variant of the process for providing the maximum or minimum value of parameters (criterion) are proposed. The physical essence of the equation of energy flows of the intensity of deformation of the mass of the medium, which depends on the method of applying mechanical forces, the degree of its previous dispersion (recipe) and its physical and mechanical properties, is considered. For a more visual view and understanding of the overall performance of the research, a scheme of causal relationships between the medium and the roll, which determine the temperature change of the dough injection process, is proposed. It is noted that the determination of the influence of the temperature of deformation processes during the passage of the process of injection of the medium by roller working bodies plays an important role for calculations of the design of molding, roll-over equipment. The influence of thermal circulatory chaotic streams is considered, the character of which also leads to violations of the general heat circulation in the medium during the injection. At the same time, the level of such violations may be sufficiently deep with changes in the directions in their contours that influence the process, according to each particular period of the deformation stage in the injection site of the molding machine. Partly revealed methods for determining the change in temperature fluxes in the dough and on the surface of the roll. On the basis of which the change of the energy potential in the interaction of the viscous medium with rotating roller working bodies in the molding machine is considered. An exchange of energy between moving particles is discovered due to collisions of molecules of a more heated part of the body with a greater energy and the transfer of the energy particle to adjacent particles with less energy. It is noted that the definition of temperature fluxes during the process of injection of the medium by roller working bodies plays an important role in calculating the design of molding, roll-over, mixing equipment. The obtained data answer a number of questions about the possibility of thermoregulation of the process of the work of the working bodies into the environment.A set of measures for measuring the temperature during the use of devices was carried out. On the basis of their data, a real temperature change in the roller unit of the molding machine is considered, with a comparative analysis of existing ones with a newly designed design. The change of the energy potential in the interaction of the viscous medium with rotating roller working bodies in the molding machine is considered. An exchange of energy between moving particles is discovered due to collisions of molecules of a more heated part of the body with a greater energy and the transfer of the energy particle to adjacent particles with less energy. It is noted that the definition of temperature fluxes during the process of injection of the medium by roller working bodies plays an important role in calculating the design of molding, roll-over, mixing equipment. The obtained data answer a number of questions about the possibility of thermoregulation of the process of the working bodies into the environment. The essence of formation of temperature fluxes is revealed and the method of their determination in a roller assembly of a molding machine with a comparative analysis of existing ones with a newly designed design is proposed.

Global Circulation of Latent Heat in the Earth’s Atmosphere According to Data from Satellite Radiothermovision

The methodical bases and some results of using satellite radiothermovision to study global atmospheric latent heat circulation according to the data of regular satellite radiothermal monitoring are described. This approach does not use an a priori model of circulation; it implements an objective procedure for the analysis of the dynamics of periodically measured fields of total precipitable water. The reconstructed directions and the values of the mean-zonal transport velocity, the average position of the thermal equator at ~5° N, and the positions of the axis of the intertropical convergence zone over individual oceans are very consistent with the known results of independent observations and numerical modeling. Some problematic aspects of the analysis procedure are discussed.

Experimental and numerical investigations of thermal performance of Al2O3/water nanofluid for a combi boiler with double heat exchangers

Purpose This study aims to focus on usage of Al2O3/water nanofluid as working fluid in a combi boiler. The plate heat exchanger located at the bottom of the combi boiler has been used for heating the domestic water in the present study. Al2O3/water nanofluid has also been used in obtaining of the heat energy provided from combustion. Therefore, thermal performance of Al2O3/water has been determined by comparing water and nanofluid-water mixture. The present study also investigates heat transfer rates as numerical and experimental for varying cold side outlet temperatures, comparatively. Design/methodology/approach The present study has included both experimental and numerical methodologies. The experimental setup consists of main heat exchanger, atmospheric burner, circulation pump and plate-type heat exchanger in which the Al2O3/water nanofluid was used as working fluid to heat the domestic water. In the numerical part of the study, a commercial computational fluid dynamic code has been used to model heat rate and thermal efficiency of the heat exchanger used. Findings It has been concluded that the predicted results are in satisfactorily good agreement with the measured data. In the experimental part of the study, the flow rate of Al2O3/water nanofluid was kept constant during the experiments. The flow rates of the water by which the heated Al2O3/water nanofluid mixture was cooled via the plate heat exchanger have been changed as 3, 4, 5 and 6 lpm. The domestic water temperatures that were kept constant have also been changed as 40°C, 45°C, 50°C, 55°C and 60°C. It has been concluded that the Al2O3/water nanofluid thermal efficiency has been 16 per cent better than pure water. Originality/value The main originality of the present study is that thermal efficiency of the plate-type heat exchanger when Al2O3/water mixture nanofluids are used as there are limited studies related to the usage of Al2O3/water mixture nanofluids in the plate-type heat exchanger not only experimental but also numerical methodologies.

The Coupled Dynamic and Thermodynamic Processes for Secondary Eyewall Formation

AbstractUsing a previously documented successful simulation of secondary eyewall formation (SEF), the coupled dynamic and thermodynamic processes during SEF are investigated from an axisymmetric mean perspective. The budgets of momentum, density potential temperature, and radial pressure gradient force (PGF) with very small residuals reveal that rather than a single process dominating, the SEF is the consequence of tight coupling processes between the hurricane tangential wind, transverse circulation, diabatic heating, mean and eddy fluxes of momentum and heat, and the hurricane boundary layer. The collective actions of these coupling processes generate the following conditions for the SEF: (i) along with slow eyewall contraction, the azimuthal‐mean tangential wind increases on the inner side of the eyewall; (ii) while the regions in the eye and beyond the eyewall are warming, a lesser warming or cooling zone sandwiched between these two warming regions appears near the axis of maximum vertical velocity; (iii) low‐level pressure decreases (increases) with the column‐integrated warming (cooling); the increment in the PGF beyond the eyewall brings about a significant low‐level radial and tangential wind increment at SEF radii, and (iv) the hurricane boundary layer radial flow corresponding to the PGF increment enhances the convergence of moisture and angular momentum within the SEF radii. Eventually, these processes result in the SEF.

Highly Energy-Efficient Combination of Dehydrogenation of Methylcyclohexane and Hydrogen-Based Power Generation

Hydrogen, H2, has been well known as one of potential energy storages in utilization of renewable energy with its intermittent characteristic. However, H2, which is in gas phase at standard pressure and temperature, has challenging problem of storage, transportation, and low volumetric energy density. As one of the solution, H2 storage in (C7H8)/methylcyclohexane (MCH, C7H14) cycle is one of the effective and reversible methods. In this study, an integrated power generation cycle is investigated, including the the dehydrogenation process and the combined cycle power generation. Comprehensive analysis on heat circulation was performed through an enhanced process integration to ensure the high energy-efficiency system. Thermal energy required for highly endothermic dehydrogenation reaction was supplied from air-fuel combustion to ensure the effective heat recovery of the system. The performance of proposed system is compared to the Graz cycle-based system, one of the cycle of power generation cycle from H2. The comparison result shows that the proposed integrated system has a significantly higher power-generating efficiency. Additionally, with dehydrogenation included in the system, the proposed system showed a system efficiency of 53.7 %, compared with the Graz cycle based system at 22.7 % under the same operating condition.

Thermodynamic mechanism of self-heat recuperative heat circulation of vapour system

Self-Heat Recuperation Technology has recently been proved to be an effective method to cut the huge energy consumption in the chemical industry. In the present paper, the thermodynamic mechanism of the self-heat recuperative heat circulation of the vapour system without chemical reaction is studied in terms of exergy analysis using process module, temperature-entropy and energy conversion diagrams. The self-heat recuperative thermal vapour cycle process was modularized by combining four types of thermodynamic elementary process modules, namely isobaric heating and cooling process modules (heat receiver (HR) and heat transmitter (HT)) and isentropic compression and expansion process modules (work receiver (WR) and work transmitter (WT)), and a heat exchange process module (heat exchanger (HX)). In the four types of thermodynamic elementary process modules (HR, HT, WR, WT), both exergy and anergy are conserved. It is only in the heat exchange process module (HX) that exergy destruction takes place and the destructed exergy transforms into the same amount of anergy due to irreversibility of heat transfer. In the self-heat exchange process, the process fluid undergoes temperature change and phase transition. Therefore, the self-heat exchange process should be divided into three stages, namely the self-heat exchange of the liquid sensible heat, the self-heat exchange of the latent heat, the self-heat exchange of the vapour sensible heat. Correspondingly three HXs are necessary, and only in these three HXs do all the exergy destructions of the self-heat recuperative thermal vapour cycle process take place. The work provided as the minimum work required for the self-heat recuperative heat circulation of the vapour system by compressing the process fluid in the vapour phase through one WR, i.e. work input, equals the sum of the exergy required to compensate for the three exergy destructions of the three HXs and the exergy required to discard waste heat to the environment. The work input eventually converts to the waste heat, i.e. heat output, the exergy of which is the exergy required to discard the waste heat to the environment and the anergy of which results from the three exergy destructions of the three HXs.

Characteristics of surface boundary layer during active and weak phases of southwest monsoon over Kochi: A tropical station

This study explores the features of atmospheric surface layer over Kochi during active and weak phases of the southwest monsoon season. The classification of active and weak phases of monsoon is made on the basis of monsoon organized convection over the region. When the monsoon organized convection is over (away from) Kochi, considered it as an active (weak) phase. The study primarily utilizes sonic anemometer data. The diurnal variation of surface fluxes and turbulent kinetic energy (TKE) during active and weak conditions are examined in addition to surface wind and temperatures. It is found that monsoon clouds spread extensively over large area stabilizes the surface layer and a drastic decrease in sensible heat flux is observed during the active monsoon conditions. The average value of momentum flux and TKE decreases, surface layer becomes stable, and Atmospheric Boundary Layer (ABL) height lowers during active monsoon phase. A significant oscillation of 3.5 h periodicity is found to be embedded in the momentum flux and in the wind speed which is attributed to the penetration of the low level monsoon circulation. Weak monsoon phase is characterized by higher value of fluxes and TKE with higher amplitude of diurnal variation due to local heating and sea breeze circulation. Unstable condition between 00:00 IST and 01:00 IST and stable conditions in the early morning is observed during both active and weak phases. It is observed that there are two different relations for the growth and dissipation of fluxes and TKE. The dissipation is faster than growth in the case of surface fluxes with temperature. The sensible heat flux, momentum flux and TKE are logarithmically related with wind speed. Sensible heat flux has logarithmic relation with temperature, whereas momentum flux and TKE have exponential relation.

Highly energy-efficient combination of dehydrogenation of methylcyclohexane and hydrogen-based power generation

Hydrogen (H2) has been well studied for its potential use in energy storage, which is particularly related with the intermittent characteristic of renewable energy sources. However, the gas form of H2 at standard pressure and temperature (STP) poses a challenging problem in terms of storage, transportation, and low volumetric energy density. An effective and reversible method for H2 storage is chemically bonded H2 used in the toluene (C7H8)/methylcyclohexane (MCH, C7H14) cycle. This study investigates a power generation system from H2 storage in MCH, involving the dehydrogenation process and the combined cycle as a power generation process. An adequate analysis of the heat circulation was performed through an enhanced process integration (EPI) to ensure the high energy-efficiency of the proposed system. A highly endothermic reaction of dehydrogenation was supplied by utilizing the energy/heat from air-fuel combustion to ensure the effective heat recovery of the system. The proposed system was analyzed through an adjustment of the main operating parameters, namely, the GT inlet pressure, GT inlet temperature, and the condenser pressure, to observe their effects on the efficiency of the system. It was found that these parameters have a significant influence on the system performance and provide the possibility of further improvement. Under optimum conditions, the proposed system can realize a very high system efficiency of 54.6%. Moreover, the proposed system is also compared to a Graz cycle-based system, which has been reported to achieve an excellent power generation cycle from H2. This result implies that the proposed integrated system leads to a significantly higher power-generating efficiency. Numerically, the proposed system demonstrated a system efficiency of 53.7% under similar conditions as the Graz cycle based system, which achieved a system efficiency of 22.7%.

Integrated system of rice production and electricity generation

Research and development of approaches to improve energy efficiency in the rice industry can help stakeholders to make informed decisions. In this study, an enhanced integrated system of both rice production and power generation was proposed. The integrated system mainly consisted of superheated steam drying, husking, polishing, torrefaction, steam gasification, and power generation. In addition, suitable technology options for power generation and rice production processes for increasing the energy efficiency were also investigated. Furthermore, to contribute to minimization of the exergy loss, recovery was performed by combining the concept of heat circulation and process integration. Results show a considerably higher energy efficiency of the proposed integrated system. In a single rice production system, processing of 200 t rice grain d−1 can generate surplus electricity of about 3.4 MW with an electricity production efficiency of about 32%. A high economic benefit could be achieved by synergetic integration in the rice industry.

Improving the Operation of Solar Water Heating Systems in Green Buildings via Optimized Control Strategies

Solar water heating (SWH) systems are well known and effective structures that transfer solar energy into thermal energy with hot water as the storage. The efficiency of an SWH system is mainly based on well-designed solar collectors and proper operation mechanisms. Although the most existing literature has focused on the efficiency enhancement of solar collectors, limited studies are devoted to improve the operating mechanism. As such, this paper studies the control mechanisms of the SWH system with a purpose so as to help the building manager to achieve targeted energy management goals. In particular, three control approaches are presented for improving the operational efficiency of the SWH system by controlling auxiliary heaters, such as heat pumps, electric heaters, and circulation pumps. The proposed approaches are developed based on different requirements of information such as the hot water demand, weather, and electricity price. Moreover, three various energy management objectives are studied with considering different scenarios in terms of real weather pattern and hot water demand of a commercial building. The results validate that the proposed approaches can improve the operation of the SWH system according to various operation objectives.

Upscale Impact of Mesoscale Disturbances of Tropical Convection on Convectively Coupled Kelvin Waves

Tropical convection associated with convectively coupled Kelvin waves (CCKWs) is typically organized by an eastward-moving synoptic-scale convective envelope with numerous embedded westward-moving mesoscale disturbances. Such a multiscale structure of tropical convection is a challenge for present-day cloud-resolving simulations and its representation in global climate models. It is of central importance to assess the upscale impact of mesoscale disturbances on CCKWs as mesoscale disturbances propagate at various tilt angles and speeds. Besides, it is still poorly understood whether the front-to-rear-tilted vertical structure of CCKWs can be induced by the upscale impact of mesoscale disturbances in the presence of upright mean heating. Here, a simple multiscale model is used to capture this multiscale structure, where mesoscale fluctuations are directly driven by mesoscale heating and synoptic-scale circulation is forced by mean heating and eddy transfer of momentum and temperature. The results show that the upscale impact of mesoscale disturbances that propagate at tilt angles of 110°–250° induces negative lower-tropospheric potential temperature anomalies in the leading edge, providing favorable conditions for shallow convection in a moist environment, while the remaining tilt-angle cases have opposite effects. Even in the presence of upright mean heating, the front-to-rear-tilted synoptic-scale circulation can still be induced by eddy terms at tilt angles of 120°–240°. In the case with fast-propagating mesoscale heating, positive potential temperature anomalies are induced in the lower troposphere, suppressing convection in a moist environment. This simple model also reproduces convective momentum transport and CCKWs in agreement with results from a recent cloud-resolving simulation.

Seasonal variations of hydrographic parameters off the Sudanese coast of the Red Sea, 2009–2015

The variations of temperature and salinity in the Sudanese coastal zone of the Red Sea are studied for the first time using measurements acquired from survey cruises during 2009–2013 and from a mooring during 2014–2015. The measurements show that temperature and salinity variability above the permanent pycnocline is dominated by seasonal signals, similar in character to seasonal temperature and salinity oscillations observed further north on the eastern side of the Red Sea. Using estimates of heat flux, circulation and horizontal temperature/salinity gradients derived from a number of sources, we determined that the observed seasonal signals of temperature and salinity are not the product of local heat and mass flux alone, but are also due to alongshore advection of waters with spatially varying temperature and salinity. As the temperature and salinity gradients, characterized by warmer and less saline water to the south, exhibit little seasonal variation, the seasonal salinity and temperature variations are closely linked to an observed seasonal oscillation in the along-shore flow, which also has a mean northward component. We find that the inclusion of the advection terms in the heat and mass balance has two principal effects on the computed temperature and salinity series. One is that the steady influx of warmer and less saline water from the south counteracts the long-term trend of declining temperatures and rising salinities computed with only the local surface flux terms, and produces a long-term steady state in temperature and salinity. The second effect is produced by the seasonal alongshore velocity oscillation and most profoundly affects the computed salinity, which shows no seasonal signal without the inclusion of the advective term. In both the observations and computed results, the seasonal salinity signal lags that of temperature by roughly 3 months.