Dataset of Comprehensive Thermal Performance on Cooling the Hot Tube Surfaces of Vortex Tube at Different Pressure and Fraction

The performance of the vortex tube is low compared to a conventional heat pump engine based on Freon refrigerants, and therefore, there is a need for an experiment on how to improve its efficiency. This data article aims to analyze the effect of the new vortex tube design on cold temperature (Tc), hot temperature (Th), delta cold temperature (ΔTc), delta hot temperature (ΔTh), heat transferred as cooling effect (Q˙c), heat transferred as heating effect (Q˙h), isentropic efficiency as cooling effect (ηisc), isentropic efficiency as heating effect (ηisc), the coefficient of performance refrigeration (COPref), and coefficient of performance heat pump (COPh), which is tested based on pressure and fraction variations. The data were obtained from the experimental measurements. Data were collected at conditions with temperature controlled at 27 ± 0.1°C. All measuring instruments were supposed to be consistent for at least 5 min for data to be collected, although retrieval was conducted 4 times.


Specifications
Engineering, Mechanical Engineering Specific subject area Heat transfer, Fluid dynamics, Thermodynamics, Heat and mass transfer, Thermophysical property measurement, Cryogenics, Counter-flow Ranque-Hilsch Vortex Tube, Heat Pump. Type of data Table  Image Figure How data were acquired Data were collected from the experimental measurements and mathematical calculations. Measuring instruments used include pressure gauge, flowmeter (air), anemometer, thermocouple, flowmeter (water), and data acquisition. For mathematical calculations using a personal computer with Microsoft Office Excel software. Data format Raw Data Parameters for data collection The parameters for experimental data include the temperature of the air to the inlet, room air, air from hot and cold outlets, and water to the cooling tube. It also included the volume of the airflow rate to the inlet, the pressure of the air entering the channel to the inlet, maximum air velocity from cold outlet, testing air velocity of n th -testing from cold outlet, and cooling water flow rate volume. Description of data collection Data were collected based on the conditions of the test chamber, whose temperature was controlled at 27 ± 0.1 °C.

Value of the data
• The data describes comprehensive RHVT thermal performance on the new vortex tube design tested based on pressure and fraction variations. • The data illustrates the design specifications of the new vortex tube design to improve their performance. • The data describes the installation procedures and working specifications of the measuring instruments to determine the performance on the vortex tube. • The data provides calculation procedures for mathematical analysis of the experimental measurement.

Data Description
The performance of the vortex tube is low compared to a conventional heat pump engine based on Freon refrigerants, and therefore, there is a need for an experiment on how to improve its efficiency. Furthermore, the vortex tube has several benefits, including no moving parts or mechanical wear, saving maintenance costs, no Freon use, and it is environmentally friendly [1 , 2] . According to previous studies, the parameters that might improve its performance include mass fraction, air pressure entering the inlet, material type, and geometry [3][4][5][6][7] . This experiment, therefore, aims to determine the best vortex tube performance parameters tested under variations in design, pressure and fraction. The performance dataset presented includes cold temperature ( T c ), hot temperature ( T h ), delta cold temperature ( T c ), delta hot The average temperature of cold air produced by vortex tubes with natural cooling tube types is presented in Table 1 while Table 2 shows the vortex tubes with forced cooling. Temperature data are presented using °C units.
The average temperature of hot air produced by vortex tubes with natural cooling tube types is presented in Table 3 , while Table 4 shows the vortex tubes with forced cooling. Temperature data are presented using °C units. Changes in the cold ( T c ) or hot air temperature ( T h ) is the difference in inlet temperature ( T i ) to cold outlet temperature ( T c ) or hot outlet temperature ( T h ), as shown in equation [8] The changes in the cold temperature ( T c ) of cold air produced by vortex tubes with natural cooling tube types is presented in Table 5 while Table 6 shows the vortex tubes with forced cooling. Temperature data are presented using °C units.
The hot air temperature ( T h ) of hot air produced by vortex tubes with natural cooling tube types is presented in Table 7 while Table 8 shows the vortex tubes with forced cooling. Temperature data are presented using °C units. The temperature change in the isentropic process ( T is ) is calculated by the following equation [8] Where the specific heat ratio ( γ ) is the specific heat at constant pressure ( Cp ) per specific heat at constant volume ( Cv ) [9] . Based on the Cengel Temperature change in the isentropic process ( T is ) produced by vortex tubes with natural cooling and forced cooling tube types is presented in Table 9 shows the vortex tubes with forced cooling. Temperature data are presented using °C units.
Isentropic Efficiency ( η is ) is the sum of the changes in the inlet to outlet temperature at each isentropic temperature change, as shown in the following equation [8] : The cold outlet isentropic efficiency ( η isc ) and hot outlet isentropic efficiency ( η ish ) equations are shown by the following: The Cold Isentropic Efficiency ( η isc ) of cold air produced by vortex tubes with natural cooling tube types is presented in Table 10 while Table 11 shows the vortex tubes with forced cooling. An isentropic Efficiency is a dimensionless number, expressed as a percentage number.
The Hot Isentropic Efficiency ( η ish ) of hot air produced by vortex tubes with natural cooling tube types is presented in Table 12 while Table 13 shows the vortex tubes with forced cooling. The fraction ( ɛ c ) of the cold outlet was obtained from the speed of the mass flow of air coming out, specifically ˙ m outc at each mass flow rate of air entering the inlet ˙ m in . In Eq. (8) , each air mass flow was measured at the same diameter and air pressure to obtain a simplified Eq. (9) . In general, where v cn is the speed of air coming out at the cold outlet on n-variable tested and v cmax is the maximum mass flow rate of air coming out of the cold outlet with the heat outlet tightly closed. This is meant to satisfy the law of mass balance, which states that the mass coming out of the system is the same as the mass entering the system. The formulas to adjust the size of the fraction are as follows [2 , 3] Maximum wind speed comes out of the cold outlet for each pressure is 0.5bar (8.4 m / s ), 1.0bar (11.2 m / s ), and 1.5bar (14.0 m / s ). The regulation of the air velocity for each fraction is carried out by playing the valve gap in the hot outlet, then presented in Table 14 .
The value of the volume flow rate ( ˙ V in ) for each pressure is presented in Table 15 and presented in units of m 3 / s . Based on the Cengel table appendix 1 (2006) the value of gas constant ( R ) is 0.2870 kJ / kg.K [9] . The gas density ( ρ) equation is described as;    Where ˙ m in is the air mass flow entering, while ˙ m outh is the air mass flow coming out through the hot outlet. From Eq. (5) , these variables are proportional in the inlet vortex tube. Since the instrument can only measure air conditions atthe inlet and the cold outlet, ˙ m outh could be determined through the use of the equation.
The value of the incoming mass flow on the vortex tube is [2] ˙ The mass flow that enters the inlet ( ˙ m in ) for each pressure in the Table 17 is presented in units of kg / s . Mass flow at cold outlet ( ˙ m outc _ n ) that occur at the n th cold fraction ( ε c n ) is denoted by the following equation: Mass flow out through the cold outlet in the Table 18 ˙ m outc is presented in the following table in unit kg / s . Refer to Eq. 11 , the mass flow through the hot outlet ( ˙ m outh _ n ) that occur at the n th cold fraction ( ε c n ) is denoted by the following equation: Mass flow out through the hot outlet ˙ m outh is presented in the Table 19 in unit kg / s . The amount of heat that can be transferred by the vortex tube as a cooling effect is denoted as ˙ Q c . It is obtained using the following equation [2 , 3 , 11 , 12] : Where ˙ m outc is the air mass flowing every second at the cold outlet, Cp is the capacity of air at ambient during the test, T c is the value of the air temperature through the cold outlet, and T in is the temperature of the air entering the inlet vortex tube. The T c and T in values were obtained from the data measured.
The Table 20 dan Table 21 present the heat flow rate for cold outlet in kJ / s . The amount of heat transferred by the vortex tube as a heating effect is denoted by ˙ Q h and obtained using the following equation [13] : The mass flow rate flowing at the hot outlet is denoted as ˙ m outh . The Cp value can be determined by reading the table while T is the temperature of the air coming into through the hot outlet. The Table 22 and Table 23 present the heat flow rate for hot outlet in kJ / s . The total compressed air power entering the inlet with ideal isothermal compression is as follows [3 , 6 , 7 , 13-15] : From Eq. (17) , ˙ m in is the mass flow rate of air entering the inlet channel, R is the specific gas constant, T in is the temperature of the air, and P in is the air pressure entering the inlet channel. The environmental air pressure is denoted by P atm . The Table 24 presents the total compressed air power entering the inlet in kJ / s . The coefficient of performance refrigeration (COP ref ) is a dimensionless number that measures the performance of a cooling heat pump engine when transferring heat from a cooled room [2 , 12] . For a vortex tube, it is calculated as follows [2 , 3 , 12] .
The average COP ref produced by vortex tube with natural cooling tube type is presented in Table 25 while the vortex tube with forced cooling is shown in Table 26 . COP ref numbers are dimensionless, therefore they are presented without units.
The coefficient of performance heat pumps (COP h ) is a dimensionless number that measures the performance of a heat pump engine when transferring heat to a heated chamber [2 , 12] . It was denoted as follows in the vortex tube [2 , 3 , 12] .
Table 27 and 28 shows the average COP h produced by vortex tubes with natural cooling tube types and vortex tubes with forced cooling respectively. There are no dimensions for COP h numbers.

Experimental Design, Materials, and Methods
Data collection was carried out through experimental tests and processed mathematically. The RHVTs include types A with a natural cooling process and B with the forced cooling process, both on the surfaces of the tube. The RHVT used in types A and B was counter flow and the material used in all case was aluminium, except the cooling tube of B which used the black Teflon. The inlet diameter was 5mm, while the cold and hot tube had diameters and lengths 5mm and 40mm as well as 8mm and 105mm respectively. The diameter of the inlet and outlet of the cooling tube on type B RHVT was 8mm. However, an inner tube had a diameter of 25mm and a length of 75mm. Fig. 1 shows the details of the RHVT specifications used. Types A and B had 4 nozzle holes and the air rotation is in the direction of the flow at the inlet. The nozzle hole is rectangular with dimensions of 1 × 2mm. The diameter of the round   nozzles is 8mm with a thickness of 1.5mm. The detailed specifications of the RHVT contra flow nozzles used are presented in Fig. 2 . Fig. 3 shows a series of instruments used for experimental data collection. In the Left and right sides of the figure are Type A and B vortex tubes respectively. The temperature was set at 27 o ±0.1 °C and data were recorded after 5 minutes of running.