Explore chapters and articles related to this topic
Application
Published in Benny Raphael, Construction and Building Automation, 2023
The amount of heat absorbed is calculated using the well-known formula: mass multiplied by specific heat multiplied by the change in temperature ∆T. Since the cooling load has a unit of power and not energy (it is energy per unit time), the mass should be replaced by the mass flow rate, that is, the mass flowing per unit time. Mass flow rate is equal to volumetric flow rate multiplied by density. Therefore, cooling load supplied by a coil circulating chilled water is calculated using the formula: Q=CpρGΔT Where, Q is the cooling load in Watts, Cp is the specific heat of water = 4,200 J/kg/deg, ρ is the density of water = 1000 kg/m3, G is the chilled water flow rate in m3/s, and ∆T is the difference in temperatures of supply and return water.
Experimental comparison of R290 and R600a and prediction of performance with machine learning algorithms
Published in Science and Technology for the Built Environment, 2023
Oguzhan Pektezel, Halil Ibrahim Acar
In the system, temperature, pressure, flow rate, and compressor power consumption measurements are made. Six temperature and six pressure sensors are mounted in the system. These sensors are embedded in copper pipes so that they can make the most accurate measurement by contacting the refrigerant circulating in the system. A wattmeter was used to measure the compressor power consumption. Turbine type volumetric flow meter was used to measure the refrigerant flow rate in the system. The mass flow rate used in thermodynamic calculations was obtained by multiplying the measured volumetric flow rate with the density. Besides of Coriolis type mass flow meters, it is seen that volumetric flow meters have also been used to determine the flow rate of refrigerants in previous studies available in the literature (Ko et al. 2021; Yan, Feng, and Peng 2015; Xu, Yan, and Xia 2022; Sieres and Santos 2018). Not to let any errors in measurement of refrigerant flow rate, the flow meter was mounted to the condenser exit being the liquid line of refrigeration setup. All measurements were taken with a datalogger and recorded on the computer. Table 1 presents the sensors’ brands, measuring ranges and accuracy values.
Verification of Uncertainty Distributions for Thermal-Hydraulic Mixing Parameters Used in KWU-MIX for Pressurized Thermal Shock
Published in Nuclear Technology, 2022
Some of the boundary conditions for experiment UPTF-TRAM Test C2, Run 21a2, as described by Hertlein,14 are shown in Fig. 5. Figure 5 shows the measured mass flow rate of injected water into the cold leg, with the scale on the right side of the figure. The mass flow rate, MINJ in Fig. 5, is the volumetric flow rate QINJ from Fig. 1 multiplied by the water density. The injected flow rate defines two separate test phases. The first is from the start of the test until approximately 1200 s, during which time the injected flow rate was approximately 20 kg/s. The second phase is from approximately 1750 s until the end of the test at approximately 3200 s, when the flow rate was approximately 10 kg/s. The measurement uncertainty in the mass flow rate is given by Liebert and Ahrens16 as ±0.291 kg/s.
A time-dependent vapor flow model of asphalt concrete
Published in International Journal of Pavement Engineering, 2021
Mohiuddin Ahmad, Rafiqul A Tarefder
Once the value of α is determined, Darcy’s law can be used to determine the vapour permeability as shown by Equation (5). Here, mass flow rate (gm/cm2/day) is considered instead of volumetric flow rate (cm3/cm2/day).where k is the vapour permeability of the sample, and i is the pressure gradient between two faces (i =Δh/L). The final form of vapour permeability can be expressed as:where k is the vapour permeability of the sample. Δh is the pressure difference between the two surfaces. The pressure difference is due to the vapour pressure only and can be determined by,where S is the saturation vapour pressure (cm-Hg) at a specific temperature. RH1 is the relative humidity at the source, which is 1.0, as water was used as a source during this study. RH2 = relative humidity of the chamber, which was set to 0.5. Saturation vapour pressure can be obtained using Equation (8) which depend only the temperature (Monteith and Unsworth 2007).The final formula to determine the vapour permeability of an absorbing medium like asphalt concrete can be expressed as:The units of different parameters used in this study are shown in Table 4.