Introduction
Many studies on thermal energy storage systems using ice have been reported for load leveling of electric power [1]. In particular, in a dynamic ice thermal energy storage system, cold thermal energy can be transported directly because fluid ice slurry is used as a phase change material. Moreover, ice slurries are applicable for heavy thermal loads because they have high melting heat transfer rate. However, characteristics of ice slurries in fundamental processes including generation, storage, transportation, melting and so forth, have not been described yet. Therefore, ice thermal energy storage systems could be better understood by understanding these characteristics.
In the past, storage and generation of ice slurries have been carried out by many researchers. Hirata et al. [2] proposed a method to continuously produce ice slurry using a buoyancy force. Matsumoto et al. [3] used silicon oil and water mixture emulsions as a thermal energy storage material, and could produce ice slurry having high ice packing factor (IPF). Moreover, some authors showed that permeability of an ice/water mixture varied due to storage in water [4]. Melting heat transfer of ice slurry was also investigated [5].
It is necessary to consider not only the fundamental processes but also the thermal properties of ice slurries to develop the best system, and an amount of cold thermal energy must be controlled appropriately, for designing a thermal energy storage system. Sawada et al. [6] attempted to measure latent heat of fusion of ice slurry, but their study was not satisfactory with regards to dilution heat due to variations in the concentration of solutions. Some measurements using differential scanning calorimetry (DSC) have also be...
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3.1. Effects of dilution heat
Concentration of an aqueous solution varies with changes in amounts of ice, when ice melts or solidifies in aqueous solution. Then, variation of effective latent heat of fusion due to dilution must be considered. Therefore, amounts of heat produced by varying concentrations of aqueous solutions were taken from past studies.
Ulbig et al. [14] and [15] carried out precise measurements of heat generated when propylene glycol (PG), ethylene glycol (EG) and ethanol (ET) were diluted with water, respectively. Hubert et al. [16] showed heat absorption by infinite dilution of NaCl solution with water, and Khrenova et al. [17] showed heat absorption by infinite dilution of NaNO3 solution. Using these results, heat from mixing or dilution at 25 °C for each solution was approximated using a least squares method as follows, respectively:
This is by using the same mass and realizing that the specific heat of both the regular water and the hot water are the same. In our procedure, 100 mL of hot water was mixed with 100 mL of the regular water; therefore, the masses in Equation 3 cancel out (the densities of the water at different temperatures aren’t exactly the same, but the difference is negligible). This leads to the change in temperature of the hot water equaling the negative change of temperature in the regular water, shown as:
When preformed each of these experiments with each temperature of water, plugging them into the equation (Delta)(Ti – hot – Tf) T Hot x Cp x Mass(Cold) = (Delta)(Tf – Ti – Cold) T Cold x Cp x Mass(Hot)(d
The temperature probe was placed into the test tube and recorded the temperature of the freezing solution using Logger Pro software. The test tube was held against the inner glass of the ice bath beaker so the test tube was visible to see when the solution froze over. Once the freezing point was measured, the temperature stopped being monitored and the data was recorded. The steps mentioned above for finding the freezing point, also known as ΔTf, was replicated for the 0.0, 0.4, and 0.6 concentrations. To find the freezing point depression, the equation ΔTf = imKf was used. The molality (m) of each solution was then calculated dividing moles of solute by kilograms of solvent, and the Kf value for magnesium chloride is known to be -1.86. Since magnesium chloride breaks down into three ions in deionized water, it was concluded that the Van’t Hoff factor couldn’t exceed three. For better accuracy, the experiment explained above for finding the freezing point depression and Van’t Hoff factor was re-conducted exactly the same to determine more accurate results. Again, the molality of each solution was calculated, and a graph expressing the change in freezing temperature verses molality
An Investigation Into How the Thickness of Insulation Affects the Time a Drink Takes to Cool Down
This is expressed as Δ +ve (delta positive). If the total energy put in is less than the energy created, then the substance warms up (it is exothermic). This is expressed as Δ -ve (delta negative). I will investigate eight different alcohols using an alcohol or spirit burner, to measure the energy change during burning by measuring the change in temperature of some water held in a container.
The term snow is usually restricted to material that fall during precipitation in the form of small white ice crystals formed directly from the water vapour of the air at a temperature of less than 0°C and has not changed much since it fell. A fall of snow on a glacier surface is the first step in the formation of glacier ice, a process that is often long and complex (Cuffey and Paterson, 2010). The transformation of snow to ice occurs in the top layers of the glaciers and the time of the transformation depends mostly on the temperature. Snow develops into ice much more rapidly on Temperate glaciers, where periods of melting alternate with periods when wet snow refreezes, than in Polar glaciers, where the temperature remains well below the freezing point throughout the year. The density of new snow as it falls on glacier surface depends mostly on the weather conditions. In clam conditions, the density of new snow is ρs ≈ 50 – 70 kg m-3 (Table 1.1). If it is windy, there is breaking of the corners of snowflakes, and the density is more like ρs ≈ 100 kg m-3. After the snow has fallen on the surface, there are three processes that are all active together and work to transform the snow to ice.
Introduction: A phase change is a result from the kinetic energy (heat) either decreasing or increasing to change the state of matter (i.e. water, liquid, or gas.) Thus saying, freezing is the phase change from a liquid to a solid which results from less kinetic energy/heat. Also, melting is the phase change from a solid to a liquid which results from adding kinetic energy/heat. So, the freezing and melting point of something is the temperature at which these phase changes occur. Therefore, a phase change will occur when a vial of 10 mL of water is placed into a cup of crushed ice mixed with four spoonfuls with 5 mL of sodium chloride for 30 minutes. If 10 mL of water is placed in an ice bath, it will then freeze at 5 degrees Celsius because the kinetic energy will leave quicker with the ice involved. The purpose of this lab is to observe what temperature the water must be to undergo a phase change.
EG, if the water was 23 degrees I would heat the water to 33 degrees. Make sure that the fuel is weighed correctly after experiment, and recorded. By doing these checks, it means that all the experiments will be fun the same. This means the test will all be fair. Prediction I think the more bonds in the alcohol molecule structure means that more heat energy will be produced when the bonds are broken and so less fuel will be used, as the heating temperature will be higher, so it will not take as long to heat.
Specific heat capacity of aqueous solution (taken as water = 4.18 J.g-1.K-1). T = Temperature change (oK). We can thus determine the enthalpy changes of reaction 1 and reaction 2 using the mean (14) of the data obtained. Reaction 1: H = 50 x 4.18 x -2.12.
An ice rink is approximately 1,600 meters. Therefore, filling a rink 2 cm requires 32 million grams of water. Cooling this water to 0° Celsius requires 2.7 billion joules which is a lot of energy. Turning this liquid into a solid requires more energy called the latent heat of fusion which is equivalent to 340 J/g (Haché 4).
The observation from what I saw was impressive to be seen in the class.In the research I learned that dry ice was made from degrees that are below than 10 degrees.You had as welll put in water to make the smoke effect work.Another thing is that be sure not to touch the plate beacause the plate is hot.It started boiling and crazy as well.
be yes as I will then be able to use enthalpy change of reaction to
The mechanical properties of sea ice are dependent on ice crystal structure, elastic modulus, grain size, tensile and compressive strength, etc. All these factors should be taken into account to model ice accurately. To have a proper understanding of the ice failure behavior...
Ice melts when in contact with salt because adding salt to the system will disturb the equilibrium,( a state in which opposing forces are balanced). The rate of melting is unchanged by the presence of a foreign material. Melting occurs faster than freezing. Salt lowers the freezing point of water. It makes a brine with the film of surface water. Any temperature above thing above the temperature of 32*F makes it possible for ice to melt. The higher the heat, the faster it melts.
The purpose of this project was to determine if algae would produce more energy than sunflower oil and canola oil. The hypothesis was that algae would produce more energy. The type of algae that was used for the experiment was chlorella. The project experiment involved growing algae in water which was placed under a carbon dioxide tank. The algae required a 12 hour light cycle per day to grow efficiently. Once grown, the algae was placed into a bomb calorimeter to measure the amount of heat energy it produces. Since there wasn’t a high quantity of algae, it was mixed in with sunflower oil. Subsequently, the sunflower oil and canola oil were also tested in the bomb calorimeter to measure the amount of heat energy they generate. The algae produced - 56.2670 kJ/g compared to sunflower oil producing -36.5578 kJ/g and canola oil producing -3.4893 kJ/g in the bomb calorimeter. This result confirms that the algae produces more than sunflower oil and canola oil.