Pressure drop and heat transfer data accompanying Chapter 5 of thesis "Advanced magnetocaloric regenerators for heat 
pump applications"

We investigated the flow and heat transfer characteristics of blocks made from MnFePSi magnetocaloric material 
produced using an extrusion-based additive manufacturing technique. An experimental setup was developed to collect 
data on pressure drop, flow rate, bulk fluid temperature, and solid surface temperature. Six samples were tested, 
each fabricated with varying fiber diameters and inter-fiber spacings, covering a range of void fractions and 
surface areas. The overlall dimensions of the samples  were 16 x 16 x 6 mm^3. Pressure drop experiments were 
conducted for each sample at three distinct temperatures, approximately 7 °C, 22 °C, and 50 °C. For each temperature, 
the flow rate ranged from values above 2 Lpm to below 0.4 Lpm. Heat transfer experiments were performed by 
self-heating the samples using electrical current to create a temperature difference with the water stream. The 
temperatures of the 4 surfaces of the blocks parallel to the flow direction were recorded, and a heat transfer model 
was used to derive heat transfer coefficients. 

The dataset consists of .csv files generated by a custom-developed data logging system. The data is classified in
two folders, one for the pressure drop measurements and the other for the heat transfer experiments. Within the
pressure drop folder, six sub-directories are placed, each corresponding to one of the six samples used in the 
investigation. These folders are named using the sample IDs. Within each one of these six folders there are either
2 or 3 files, each corresponding to pressure drop data collected at a different fluid temperature. The file names 
contain the following information: date, sample ID, type of experiment (press_drop is used in this case), 
approximate temperature. On the other hand, there are only two .csv files in the heat transfer folder, corresponding 
to the heat transfer experiments performed with two samples. The experiments of the other four samples were not 
included in this repository nor in the thesis, for they were considered failed experiments.

The following nomenclature is used in the files:


Current_shunt		electrical current			[A]
Diff_press		differential pressure across samples	[kPa]
Diff_press_filter	differential pressure accross a filters	[kPa]
Resistance		electrical resistance 			[Ohm]
t			time					[s]
T			temperature				[°C]
V_block_prob		voltage drop across the block		[V]
V_flow			volumetric flow rate			[Lpm]
V_plates		voltage drop across copper plates	[V]


Subscripts

block_X			refers to one of the surfaces of the sample (X may be 1, 2, 3, 4, top, bottom, left, or right)
water_in		water entering the sample holder
water_out		water leaving the sample holder
ambient			ambient temperature
DMM1			digital multi meter 1

Multiple time columns show the same values. This is because the corresponding data comes from the same multimeter.
Because we did not use a real-time data logging system, the time stamps correspond to responses of the data
logging Python script when the function float(time.time() - startTime) is called.

The only columns actually used in the pressure drop data analysis are the following:

T_water_in
T_water_out
V_flow
Diff_press

The Diff_press column was corrected to take into account a post-calibration of the pressure sensor and the 
hydrostatic pressure. The correction function is as follows:

Out_voltage_pressure_sensor = 5.07 * (0.009 * Diff_press + 0.04)
DP_corrected = (Out_voltage_pressure_sensor - 0.21057) / ((0.2762 - 0.21056) / 1.4764995)
Dynamic_diff_press = DP_corrected - density((T_water_in + T_water_out)/2) * g * h

Where g is the gravity constant and h = 0.109 [m] is the height difference between sensing points of the differential
pressure sensor. 

In the heat transfer analysis all columns except the Diff_press columns are used.

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SEM images of samples used in Chapter 5 of PhD thesis titled "Advance magnetocaloric regenerators for heat pump 
applications"

The SEM data is organized in six folders, named using the ID tags of the blocks. Images were uploaded as .tif files. 
A .txt file is included along with each image, containing some general information given by the SEM device: date, 
time, magnification (MAG), stage position, working distance (WD), acceleration voltage (ACCEL_VOLT), and probe 
current (SPOT_SIZE). 


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Data processing software

A link to a git repository has been also included in this 4TU repository. Multiple scripts used for data collection
and analysis can be found in there. The git repository includes a README.md file with further details.