Volume Of Hot Water Research Articles

Figure of merit for solar domestic hot water systems

New software has been developed, adapted to International Standard ISO 9459-2, in which the daily solar domestic hot water (SDHW) system operation is modeled with a heat-limited consumption scheme, fixed by a nominal temperature, (Tdn), and a daily nominal hot water volume production, (Vdn). Solar energy is traced to its end forms; overheating in summer months, remaining in storage to be used the next day, lost through storage tank surface and drawn-off in the useful hot water. Auxiliary heat to comply with nominal settings is also calculated. For commercial reasons it is becoming more and more necessary to have an effective way of classifying SDHW systems. Our proposal is to use as figure of merit, the rate between the hot water produced in one year and the auxiliary heat needed, (L/kWh), calculated when the daily extraction is 2/3 of the storage volume, (Vdn=2/3 Vs) and the temperature (Tdn) is 60°C. The draw-back of such a procedure results from observing that the value obtained is site-dependent. An alternative classification way is presented, based on a non-dimensional number that is totally site-independent.

Применение теплового воздействия в коллекторе двойной проницаемости, насыщенном высоковязкой нефтью. Теория

HEAT TREATMENT APPLICATION FOR DUAL PERMEABLE HEAVY OIL RESERVOIR. THEORY Background Designing the enhanced oil recovery (EOR) methods decision to use the thermal treatment method is usually based on the laboratory experiments. In the case of the development of heavy oil dual permeable reservoir the laboratory data are insufficient because they do not reflect the processes of oil displacement in the presence of high heterogeneity of reservoir permability. Aims and Objectives to establish the influence of heterogeneity of reservoir permeability for dual permeable collector on the efficiency of heat treatment. Methods There were applied the hydrodynamic model which, on the one hand, contains data from laboratory studies, and on the other hand, simulates the macroproperties of collector. Results 1. Efficiency of heat treatment, i.e. hot water injection to the dual permeable reservoir depends on the residual oil production of fractured layers. Heat treatment of heavy oil deposits in dual permeable reservoir has a significant results in the case when the fractured layer till the beginning of the technology application has not been developed, but the effect from the use of that technology is significantly delayed from the start of application of the technology, i.e., requires injection of large volumes of hot water. 2. If the fractured layer till the beginning of the technology application is partially or fully developed, then the effect of injection of hot water is intermittent and not significant in magnitude. At the same time there is a rapid growth of watering; during the heat treatment of dual permeable reservoirs watering is almost always higher than during the isothermal flooding.

Effective cleaning of the milking machine

An effective plant-cleaning regime for the milking equipment is essential to maintain milk quality and reduce bacterial cross infection between cows. Effective cleaning and disinfection requires adequate volumes of hot water at a suitable temperature, with a suitable sanitising product, at the appropriate rate, circulated for the correct time. The routine needs to be monitored and any procedural drift identified and addressed. Please note: Wiley-Blackwell are not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Dynamic performance estimation of small-scale solar cogeneration with an organic Rankine cycle using a scroll expander

Small-scale solar thermal cogeneration shows promise as an effective way to get increased benefit out of a given solar availability, since it does not waste potential during summer after the water capacity is heated. In this paper a scroll expander is tested in a small organic Rankine cycle (ORC) and used to calibrate a static expander model. Validation of the scroll expander model shows agreement generally within 10% for the shaft power, 5% for the rotational speed and 6 K for the exhaust temperature, with some outliers at very low pressure ratios. This calibrated model is then incorporated into a larger dynamic model of a solar thermal cogeneration system, designed for some larger dwelling unit or small commercial establishment that requires a larger volume of hot water. An annual simulation is conducted using a collector area of 50 m2, and the scroll expander shows a maximum isentropic efficiency of 59% while the ORC efficiency is 3.47%. The total energy produced is 1710 kWh and the hot water available is on average 2540 L/day. The maximum instantaneous power that can be produced by the system is 676 W, and it is possible to shift the time period that the system is producing power to match the peak demand period by adjusting the solar store volume.

Domestic hot water consumption estimates for solar thermal system sizing

Accurate domestic-hot water (DHW) consumption information is useful for solar-thermal-hot-water-system designers and policy makers supporting solar-thermal-incentive programs. Conducting field studies of DHW-consumption patterns is difficult and costly, and as a result, there are few studies available in the body of literature. Several DHW models exist, however these aggregate models are often dated and most fail to identify the influence of the number of occupants in the dwelling, instead relying on a standard-per-capita consumption. The standard of 60 liters/capita/day (lcd) is found to be accurate for households of 4 or more occupants, but significantly under estimates per-capita-hot-water consumption for households with 3 or fewer occupants, consequently, under estimating the energy and GHG-emissions savings of solar-DHW programs [1]. The new estimate presented here addresses these issues. This study was conducted using utility-billing data, and occupant responses from a survey of 1594 residences. The data includes annual total-water use, energy consumption, costs, and basic information about the residence and occupants. The method isolates average-oil used in water heaters and then estimates system performance to calculate the volume of hot water heated. The findings include total-water use, oil consumption for water heating, and DHW use based on occupancy for households of 1 through 6 occupants.

Sensitivity Analysis of Saturated Steam Production in Parabolic Trough Collectors

Thermal and synthetic oil is the most common fluid used as heat transfer fluid in parabolic trough collectors for steam generation or producing high volumes of hot water. The solar field configuration using oil is the unfired-boiler configuration. The use of water as alternative heat transfer fluid is not new but is not extended. This paper presents numerical results related to the thermal-hydraulic behavior of solar fields producing saturated steam for industrial process heat applications considering two different types of small sized parabolic-trough collectors which are available in the market. A sensitivity analysis was conducted considering different design criteria and working conditions. The effect of inlet water pressure, temperature and DNI is analyzed. One of the conclusions extracted from the numerical results is that low working pressures can originate high pressure losses in the solar field depending on the absorber pipe diameter and steam pressure and, consequently, steam temperature in the solar field outlet can vary a lot even under small transients.

The effect of black tea on risk factors of cardiovascular disease in a normal population

ObjectivesA prospective randomized controlled clinical trial determined the effect of Mauritian black tea consumption on fasting blood plasma levels of glucose, lipid profiles and antioxidant status in a normal population. MethodsThe study group (71%) consumed 3 x 200ml of black tea infusate/day for 12weeks without additives followed by a 3week wash-out. The control group (29%) consumed equivalent volume of hot water for same intervention period. ResultsThe tea used had high levels of gallic acid derivatives (50±0.4mg/L), flavan-3-ols (42±2mg/L), flavonols (32±1mg/L) and theaflavins (90±1mg/L). Daily 9g supplementation of black tea infusate induced, in a normal population, a highly significant decrease of fasting serum glucose (18.4%; p<0.001) and triglyceride levels (35.8%; p<0.01), a significant decrease in LDL/HDL plasma cholesterol ratio (16.6%; p<0.05) and a non significant increase in HDL plasma cholesterol levels (20.3%), while a highly significant rise in plasma antioxidant propensity (FRAP: 418%; p<0.001) was noted . ConclusionBlack tea consumed within a normal diet contributes to a decrease of independent cardiovascular risk factors and improves the overall antioxidant status in humans.

Black tea reduces uric acid and C-reactive protein levels in humans susceptible to cardiovascular diseases

The effect of black tea on the level of uric acid (UA) and C-reactive proteins (CRP) in humans susceptible to ischemic heart diseases was assessed in a prospective randomized controlled study. The study group consumed 9 g of black tea (equivalent to three cups of tea) daily for 12 weeks without additives followed by a 3-week wash-out (with control group consuming equivalent volume of hot water). Black tea consumption induced a highly significant decrease in the high uric acid baseline groups >6 mg/dL by 8.5%; p < 0.05. For men and women in the base line group >7 mg/dL, the decrease was 9.4% and 7.1%, respectively. In the low baseline serum uric acid levels there was a non-significant increase of 3.7% and 15% in men and women, respectively. C-reactive protein in the high risk group >3 mg/L was significantly decreased by 53.4% and 41.1% in men and women, respectively. For the non-supplemented group in this range the changes were 3.7% decrease for men and 2.9% increase for women. Tea supplementation-associated decrease in plasma uric acid and C-reactive protein levels may benefit humans at high risk of cardiovascular events and may augment drug therapy.

Performance analysis of a CO2 heat pump water heating system under a daily change in a standardized demand

Air-to-water heat pumps using CO2 as a natural refrigerant have been developed and commercialized. They are expected to contribute to energy saving in residential hot water supply. The objective of the research is to analyze the performance of a water heating system composed of a CO2 heat pump and a hot water storage tank by numerical simulation. In this paper, the system performance is analyzed under a daily change in a standardized hot water demand, and some features of the temperature distribution in the storage tank and the system performance criteria such as coefficient of performance, storage and system efficiencies, and volumes of stored and unused hot water are investigated. It turns out that the daily change in the hot water demand does not significantly affect the daily averages of the COP, and storage and system efficiencies, while it significantly affects not only the daily change in the volume of hot water unused after the tapping mode, but also that in the volume of hot water stored after the charging mode. The influence of the daily change in the hot water demand on the volumes of stored and unused hot water is clarified quantitatively.

Freeze corer No. 3 for lake sediments

Freezing of sediment in situ at the lake bottom using a freeze corer has become an important method for taking samples of soft sediments aimed for detailed stratigraphic analyses. Over the past decades a variety of freeze corers have been designed, from very simple metal tubes filled with dry ice that are dropped into the sediment to high-tech samplers using electric pumps, hydraulics and liquid nitrogen. The freeze corer described here is a compromise of getting good samples without a too complicated technique. It is designed for coring from lake ice, using a steel wire with a stopper on the ice to keep the corer in fixed position during freezing. It consists of a thermos connected to a thin freeze wedge (width 15 cm, length 100 cm, max thickness 6 cm). The dry ice is kept in the thermos until the freeze wedge has been lowered into the sediment to avoid water freezing on the wedge during descent through the water column; a wet steel-wedge surface disturbs the sediment stratigraphy less than a wedge on which rapid freezing occurs. The dry ice is kept in the thermos by a trapdoor that is opened by a messenger. When the trapdoor is opened the dry ice begins to drop into the wedge, which is filled with ethanol. This process continues concurrently with the consumption of ice in the wedge until the thermos is empty. Using 6–8 kg of dry ice and 4 l of ethanol (95%), a 3-cm-thick and up to 80-cm-long crust of frozen sediment is obtained in 20–25 min on each side of the wedge. The crust is easily detached intact from the wedge using a small volume of hot water, poured inside the wedge.

Outdoor test method to determine the thermal behavior of solar domestic water heating systems

The dynamics of the market, the generation of new promotion programs, fiscal incentives and many other factors are to be considered for the massive application of solar domestic water heating systems (SDWHS) mainly of the compact thermosiphon type, makes it necessary to choose simple and inexpensive procedure tests that permit to know their characteristic thermal behaviors without an official standard being necessary. Moreover, it allows the comparison among systems and offers enough and reliable information to consumers and manufacturers. In most developing countries, an official national standard for SDWHS is not available, therefore it is necessary to adopt an international test procedure in which the cost and time of implementation is very important. In this work, a simple and inexpensive test method to determine the thermal behavior of SDWHS is proposed. Even though these procedure tests do not have an official standard structure they permit, by comparing different solar systems under identical solar, ambient, and initial conditions, the experimental determination of: (a) the maximum available volume of water for solar heating; (b) water temperature increment and available thermal energy at the end of the day; (c) temperature profiles (stratification) and the average temperature in the storage tank after it is homogenized; (d) the average global thermal efficiency; (e) water temperature decrement and energy lost overnight; and (f) the relationship between hot water volume and solar collector area as function of the average heating temperature. An additional proposed test permits to know the heat losses caused by the reverse flow in the collector loop. These tests will be carried out independently of the configuration between the solar collector and the storage tank, the way the fluid circulates and the type of thermal exchange. The results of this procedure test can be very useful, firstly, for the local solar manufacturers’ equipment in order to design and optimize its products comparing their systems against a reference system under identical test conditions and secondly, by the consumers in order to select the most suitable system. The resulting experimental data for a particular thermosiphon system is presented and discussed.

Adsorptive removal of phenol from aqueous phase by using a porous acrylic ester polymer

The removal of phenol from aqueous solution was examined by using a porous acrylic ester polymer (Amberlite XAD-7) as an adsorbent. Favorable phenol adsorption was observed at acidic solution pH and further increase of solution pH results in a marked decrease of adsorption capacity, and the coexisting inorganic salt NaCl exerts positive effect on the adsorption process. Adsorption isotherms of phenol were linearly correlated and found to be well represented by either the Langmuir or Freundlich isotherm model. Thermodynamic parameters such as changes in the enthalpy (Δ H), entropy (Δ S) and free energy (Δ G) indicate that phenol adsorption onto XAD-7 is an exothermic and spontaneous process in nature, and lower ambient temperature results in more favorable adsorption. Kinetic experiments at different initial solute concentrations were investigated and the pseudo-second-order kinetic model was successfully represented the kinetic data. Additionally, the column adsorption result showed that a complete removal of phenol from aqueous phase can be achieved by XAD-7 beads and the exhausted adsorbent was amenable to an entire regeneration by using ethanol as the regenerant. More interestingly, relatively more volume of hot water in place of ethanol can also achieve a similar result for repeated use of the adsorbent.

Online Fault Diagnosis of Air-conditioning Units Using Recurrent Neural Network Trained with Simulation Data

Fault detection and diagnosis (FDD) of air-conditioning systems is very important for energy saving, safety and maintenance and in high demand. The air-conditioning system is a complex and dynamic system which makes the diagnosis difficult because the observed parameters do not directly express the state of the system. On the other hand, faults analysis and fault cases collected from the actual air-conditioning system are not practicable. With due consideration of the above points, the authors propose an effective FDD method for air-conditioning systems using model simulation and Recurrent Neural Network (RNN). An air-conditioning system of a certain building is used as a model in this research. The validity of the model is confirmed by comparing the simulation data with real observations. In this study, the authors concentrated on several typical faults in both chilled and hot water volume control valves. The authors obtained the data of the normal and some fault cases in time sequence using the model simulation. As a result of the current experiments, the recognition rate was over 90% and it was demonstrated that the proposed method is suitable for practical use.

Experimental evidence that the introduced fire ant, Solenopsis invicta, does not competitively suppress co‐occurring ants in a disturbed habitat

1. The fire ant, Solenopsis invicta, is a globally distributed invasive ant that is largely restricted to disturbed habitats in its introduced range. For more than half a century, biologists have believed its success results from superior competitive abilities relative to native ant species, as well as an escape from their natural enemies. 2. We used large volumes of hot water to kill fire ant colonies, and only fire ant colonies, on experimental plots in pastures, and found that populations and diversity of co-occurring ants did not subsequently increase. 3. These results are contrary to classical predictions and indicate that S. invicta is not a superior competitor that suppresses native ants, and that the low diversity and abundance of native ants in degraded ecosystems does not result from interaction with fire ants. Instead, other factors such as prior disturbance and recruitment limitation may be the primary limiting factors for native species in these habitats.

A hybrid solar desalination and water heating system

The hybrid character of a solar desalination system consisting of a “greenhouse”- type conventional solar still coupled with a solar collector field and hot water storage tank was investigated. This system shows significantly higher distilled water output compared with that of an uncoupled still, and moreover has the advantage of supplying hot water from its storage tank. Through experimental data taken from system operation in the laboratory, the suitability of the developed “input-output” method, was proven for reliable description of the system operation. It was shown that the model previously developed is capable of estimating long-term distilled water production with deviation not higher than 3% for any considered period. Following this, a theoretical investigation of hybrid operation of the system is performed concerning reduction of produced distilled water caused by storage tank hot water draw-off of different volumes at the end of the day. The results show that draw-off of hot water volume equal to 1/4, 1/2 or 1 tank volume reduces distilled water output by 36%, 57% or 75%, respectively, by simultaneous energy output of about 1900, 3300 and 5200 MJ. From the results, the characteristic curve describing the behavior of the hybrid system was drawn, which can be used during the design phase or during usage of the system.

Internal Temperature Behavior of Baked Custard Pudding and Effects of Hot Water Volume in Baking on the Rising Temperature Speed and Products

Internal Temperature Behavior of Baked Custard Pudding and Effects of Hot Water Volume in Baking on the Rising Temperature Speed and Products

シャワーヘッド散水板の設計法に関する研究 : 穴径・散水角が適流量,快適感に及ぼす影響

For the purpose of finding out methods of designing shower heads, the effects on optimum flow rate and comfort condition were examined by using shower heads whose size and angle of holes were systematically changed. To grasp physical characteristics of each shower head, the experiments concerning the distribution of the force and the volume of water were conducted. Optimum flow rate and comfort condition data were gained by the subjective experiment, and the relations between those and the force were explained. And also, optimum flow rate and flow rate when actually taking a bath were experimented by using commercially available shower heads. As a result, optimum flow rate was strongly effected by total force when the subject was hit by shower. Optimum flow rate can be predicted by total holes area, which is determined by hole size, and hardly effected by hole angle. The result of experiment using commercially available shower heads showed that optimum flow rate is related to total holes area, and the volume of hot water by each action is in proportion to optimum flow rate.

Effect of hot water load temperature on the performance of a thermosyphon solar water heater with auxiliary electric heater

A thermosyphon solar water heating system with an in-tank auxiliary electric heater has been simulated for different hot water load temperatures using the TRNSYS simulation program. The results of the simulation show that the annual efficiency and solar fraction are functions of the hot water load temperatures. The effect of load temperature on the solar fraction is found to be very large when the daily load volume (the volume of hot water delivered to load) to collector area ratio is large. The influence of storage tank volume to collector area ratio on the efficiency of the collector is observed only when this ratio is less than or equal to 40 1 m 2 for all collector areas and load temperatures studied. Generally, the annual average storage tank temperature depends on the load temperature and had lower values for high load temperatures. The response of the system performance to the area of the collector is found to be very large when the system operates with a solar fraction below 70%.

Hydrocarbon Occurrences Near Kyle Hot Springs, Buena Vista Valley, Pershing County, Nevada: ABSTRACT

Buena Vista Valley is a small Tertiary Basin located in Northwestern Nevada. Oil was discovered in a mineral exploration hole drilled by Independence Mining Company Inc. (IMC) during October, 1993 near Kyle Hot Springs in Buena Vista Valley. The hole flowed unchecked for four and a half days, producing an estimated 500 barrels of oil with large volumes of hot water, before it was plugged and abandoned. In August of 1994 a continuous core hole was drilled by Barton/Evans to further evaluate the oil occurrences in the IMC hole. Two oil zones were found in the Barton/Evans hole, both of which have similar characteristics to the oil produced in the IMC hole. Pristane and phytane ratios (pr/ph) for oil samples from both holes are low (<0.1) which suggests that the source rock for this oil is from non marine lacustrine Tertiary sediments. There are no detectable hydrocarbons in the gas emanating from Kyle Hot Springs which indicates that the current day geothermal system is not in direct contact with any oil accumulations. Organic rich Triassic marine rocks which outcrop west of Buena Vista Valley, are over mature which supports the hypothesis that unexposed organic rich Tertiary rocks occurring in themore » deeper portions of the basin acted as the source for the oil occurrences in the IMC hole and in the Barton/Evans hole. In 1974, Standard Oil drilled an 11,000 foot well south of Buena Vista Valley in the Carson Sink and encountered organic rich Tertiary sediments at about 3500`. If this organic rich unit extends north into Buena Vista Valley, local geothermal anomalies might play an important role in the generation of oil. Earlier researches have reported that such anomalies do exist with temperature gradients approaching 100 C per kilometer west of Kyle Hot Springs in an area where gravity data suggest a relatively thick interval of Tertiary rocks have accumulated.« less

Modeling the thermal process in a shallow solar pond water heater

An investigation was undertaken to develop a mathematical model to predict the performance of shallow solar pond water heaters with dark colored water bags. Heat balance (SSP) equations were solved analytically with the Laplace transform for partial differential equations, and the method of residuals. The model was implemented with Quick Basic language in a Macintosh computer. Experimental data was gathered from an existing SSP installation at the University of Puerto Rico, Mayagüez Campus. The model gave accurate results predicting the maximum temperature and describing the performance of the pond throughout the daytime hours. Economics of the system indicate that SSPs are a feasible alternative for users of average to high volumes of hot water in Puerto Rico, and other Caribbean islands, at the current crude oil prices. This work recommends the construction of SSP in modules of 40 m 2 for practical applications.