Experimental Facility for the Study of Enhanced Refrigerants
Transcript of Experimental Facility for the Study of Enhanced Refrigerants
Experimental Facility for the Study of Enhanced Refrigerants
MEMS 1042 Semester Project
Stanley Schurdak
Project Overview
MotivationReduce annual energy cost from domestic refrigerators
Use enhanced refrigerants to reduce compressor cycle time
Shorter run time lowers energy consumption
ScopeRefrigerants with large cp-values increase heat transfer rate
Experimental facility is needed to quantify cp- values
Improved cp-values can be related to COP and cost savings
Defining Equations
Constant-pressure specific heat (cp)
Coefficient of performance ( )
Energy consumption (E)
=q Lw c
: Heat transfer rate: Refrigerant mass flow rate
T: Refrigerant temperature change
: Heat transfer rate: Compressor work
: Compressor work t : Compressor cycle time
Specific Heat Target Range
Common Refrigerants
Improved RefrigerantsFor significant savings, process cp must be 2 4 times higher
Expected range is 1.29 17.50 kJ/kg-K
Experimental facility must be designed accordingly
Refrigerant cp (-23ºC, 120 kPa) cP (Process: -23ºC 32ºC)
R-22 0.628 kJ/kg-K 0.646 kJ/kg-K
R-410a 0.788 kJ/kg-K 0.806 kJ/kg-K
R-134a 1.287 kJ/kg-K 4.735 kJ/kg-K
Basic Construction
Experimental SetupWooden crate with rigid insulation covering
Copper pipes assembled to form condenser/evaporator
Flow meter and thermocouple output to PC via DAQ
Estimated CostWood/Insulation: ~$62.73
Piping/Connections: ~$71.07
Compressor/Expansion Valve: ~$249.46
Experimental Facility
SchematicFacility consists of compressor, condenser, expansion valve, and evaporator
Components connected with copper tubing
Experimental Facility
Model
Evaporator coils
Thermocouples insertedthrough walls(not shown)
Expansion valve/flow meter assembly(not shown)
Compressor(not shown)Condenser coils
Thermocouples attached to pipes(not shown)
Sensors
Proposal AMax Machinery Piston Flow Meter 214
Accuracy: 0.2% of reading
Cost: $2450.00
Fieldpiece Clamp Thermocouple ATC1R (x2)Accuracy: 0.5ºC
Cost: $93.18
Omega Thermocouple 5TC-PVC-K-24-180Accuracy: 1.5ºC
Cost: $55.00
Sensors
Proposal BDwyer MFS2-2 Flow Meter
Accuracy: 1.0% of reading
Cost: $679.00
StopwatchesUSA Combination Thermometer/Timer (x4)Accuracy: 1.0ºC/ 1.0 Sec
Cost: $40.00
Total Sensor Cost/Overall AccuracyProposal A: $2917.18, cp 3.16%, 2.73%
Proposal B: $1037.80, cp 3.45%, 2.89%
Summary
Accuracy/Cost Comparison
Proposal A Proposal B
Materials: $423.26 $423.26
Sensors: $2917.18 $1037.80
Total Cost: $3340.44 $1412.06
Accuracy: cp 3.16%, 2.73% cp 3.45%, 2.89%
Pros: Higher accuracy; digital output allows for datastorage and analysis
Simple setup; data from only mass flow needs to be
recorded; less expensive
Cons: More expensive; flow meter could be difficult
to work with
Slightly less accurate; thermometers/timers could be inaccurate
Specific Heat Uncertainty
0.1
0.2
0.3
0.4
0.5
0.6
0.7
8 13 18 23
Un
cert
ain
ty (k
J/kg
-K)
Specific Heat (kJ/kg-K)
ucp vs. cp
Option A
Option B
3.443.443.443.443.443.453.453.453.45
8 13 18 23
Pee
rcen
t Un
cert
ain
ty
Specific Heat (kJ/kg-K)
%ucp vs. cp
Option B
3.173.173.173.173.173.173.173.173.17
8 13 18 23
Pee
rcen
t Un
cert
ain
ty
Specific Heat (kJ/kg-K)
%ucp vs. cp
Option A
COP Uncertainty
0.0480.0580.0680.0780.0880.0980.1080.1180.1280.1380.148
2 3 4 5
Un
cert
ain
ty (k
W/k
W)
(kW/kW)
u vs.
Option A
Option B
2.732.732.732.732.732.732.732.732.732.73
2 3 4 5
Per
cen
t Un
cert
ain
ty
COP (kW/kW)
%u vs.
Option A
2.882.882.892.892.892.892.892.902.902.90
2 3 4 5
Per
cen
t Un
cert
ain
ty
(kW/kW)
%u vs.
Option B
Bill of Materials
Sensor Vendor Model PriceRefrigerant Thermocouple (x2) Fieldpiece ATC1R $93.18 Box Thermocouple (x5) Omega 5TC-PVC-K-24-180 $55.00 Flow Meter Max Machinery 214 Analog $2450.00DAQ NI USB-6525 $319.00
Total Sensors: $2,917.18
Part Vendor Model PriceCompressor Samsung MK183C-L2U $151.85 Copper pipe 1/4" (50') Lowe's D 04050PS $31.07 Copper pipe 3/8" (50') D 06050PSE $49.00 Misc. Connectors Lowe's N/A $40.00 Expansion Valve Randell RF-VLV200 $97.61 Wood 2 x 4 (x3) Home Depot 161640 $8.94 Plywood (x2) Home Depot 646214 $16.16 Insulation (x2) Home Depot 45W $28.63
Total Parts: $423.26
Grand Total: $3340.44
Option A
Bill of Materials
Sensor Vendor Model PriceThermometer/Timer (x4) StopwatchesUSA 41100A $40.00 Flow Meter Dwyer MFS2-2 $625.00 Flow Meter Cable Dwyer MFS-C3 $54.00 DAQ NI USB-6525 $319.00
Total Sensors: $1037.80
Part Vendor Model PriceCompressor Samsung MK183C-L2U $151.85 Copper pipe 1/4" (50') Lowe's D 04050PS $31.07 Copper pipe 3/8" (50') Lowe's D 06050PSE $49.00 Misc. Connectors Lowe's N/A $40.00 Expansion Valve Randell RF-VLV200 $97.61 Wood 2 x 4 (x3) Home Depot 161640 $8.94 Plywood (x2) Home Depot 646214 $16.16 Insulation (x2) Home Depot 45W $28.63
Total Parts: $423.26
Grand Total: $1461.06
Option B
References
Fatouh, M., and M. El Kafafy. "Experimental Evaluation of a Domestic Refrigerator Working with LPG B.V., Oct. 2006. Web. 29 Mar. 2014.
Sonntag, Richard Edwin., C. Borgnakke, Van Wylen Gordon J., and Van WylenGordon J. Fundamentals of Thermodynamics. New York: Wiley, 2003. Print.
Equation Partials Uncertainty !Air - u!Air = ±0.0005 kg/m3
cp Air - uCp Air = ±0.0005 kJ/kg-K
VAir = LAir WAir HAir
!
"VAir
"LAir=WAirHAir
"VAir
"WAir
= LAirHAir
"VAir
"HAir
= LAirWAir
!
uVAir = uL (WAirHAir)2 + (LAirHAir)
2 + (LAirWAir)2
!
TAir =T1 +T2 +T3 +T4 +T5
5
!
"#TAir"T1
="#TAir"T2
="#TAir"T3
="#TAir"T4
="#TAir"T5
=15
!
uTAir =uT5
!TAir = Tf - Ti
!
"#TAir"Tf
=1
"#TAir"Ti
= $1
!
u"TAir =uTAir2
!t - u"t = ±1 sec
!
˙ m -
!
u ˙ m = ±0.2%
!TR = TR2 – TR1
!
"#TR"TR2
=1
"#TR"TR1
= $1
!
u"TR =uTR2
!
˙ q L ="AirVAirc pAir#TAir
#t
!
" ˙ q L"#Air
=VAircpAir$TAir
$t" ˙ q L"VAir
=#Airc pAir$TAir
$t" ˙ q L"cpAir
=#AirVAir$TAir
$t
" ˙ q L"$TAir
=#AirVAirc pAir
$t" ˙ q L"$t
=%#AirVAirc pAir$TAir
$t 2
!
u ˙ q L=
VAircpAir"TAir
"tu#Air
$
% &
'
( )
2
+#Airc pAir"TAir
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$
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( )
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+ , ,
!
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$
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( )
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!
+"VAir#Airc pAir$TAir
$t 2u$tAir
%
& '
(
) *
2 +
, - -
12
!
cp =˙ q L
˙ m "TR
!
"cp
" ˙ q L=
1˙ m #TR
"cp
" ˙ m =
$ ˙ q L˙ m 2#TR
"cp
"#TR
=$ ˙ q L
˙ m #TR2
!
ucp =u ˙ q L
˙ m "T#
$ %
&
' (
2
+˙ q Lu ˙ m
˙ m 2"T#
$ %
&
' (
2
+˙ q Lu"T
˙ m "T 2
#
$ %
&
' (
2
!
˙ w c -
!
u ˙ w c =0.0005 kJ
!
" =˙ q L˙ w c
!
"#" ˙ w c
=$ ˙ q L˙ w c
2
"#" ˙ q L
=1˙ w c
!
u" =u ˙ q L
˙ w c
#
$ %
&
' (
2
+) ˙ q Lu ˙ w c
˙ w c2
#
$ %
&
' (
2
!
E = ˙ w c"t
!
"E" ˙ w c
= #t
"E"#t
= ˙ w c
!
uE = "tu ˙ w c( )2+ ˙ w cu"t( )2