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Valorisation of Low-Grade Waste Heat Felix Ziegler | Institut für Energietechnik Vision: No useful heat flow without use!
Valorisation of Low-Grade Waste Heat
Felix Ziegler | Institut für Energietechnik
Vision: No useful heat flow without use!
Felix Ziegler | Institut für Energietechnik
OptionsAbsorption coolingSteam jet cycleHonigmann cycleEfficiency, and cost
Valorisation of Low-Grade Waste Heat
Valorisation of low-grade waste heat | Felix Ziegler | 3
in
out
in
out
in
out
in
out
in
out
in
in
in
out
out
Temperature of heat flow
upgraded:T3=120°C
source: T2=80°C
work: T→∞
cold: T0=5°C
ambient: T1=35°C
#1 #2 #3 #4 #5
High source:T4=180°C
Valorisation of low-grade waste heat | Felix Ziegler | 4
in
out
in
out
in
out
in
out
in
out
in
in
in
out
out
Temperature of heat flow
upgraded:T3=120°C
source: T2=80°C
work: T→∞
cold: T0=-150°C
ambient: T1=35°C
High source:T4=180°C
#1 #2 #3 #4 #5
Valorisation of low-grade waste heat | Felix Ziegler | 5
Cold is produced from heat
Q1´´
Q0
EV
K
V
Q2
A
Q1´
LEVLP
LWT
G
Cold
Drive
Heat sink
Heat sink
Single-effect absorption chiller
Valorisation of low-grade waste heat | Felix Ziegler | 6
Nominal cooling capacity 50kW
Valorisation of low-grade waste heat | Felix Ziegler | 7
Dt@40kW=13K 40K
Variation of driving heat @ tsink=30°C, Vsink=3,8l/s, tcold=21/16°C
50 60 70 80 90 1000
10
20
30
40
50
60
70
Driving temperature in [°C]
0,9 l/s0,6 l/s
0,3 l/s
0,1 l/sCoo
ling
capa
city
[kW
]
Valorisation of low-grade waste heat | Felix Ziegler | 8
Control: Minimisation of auxiliaries
Control strategy SEERel SEERth
#1: Classic drive(Temperature) 13 0,75
#2: Heat sink (Temperature and flow rate) 19 0,75
#3: Drive (Temperature and flow rate) 14 0,75
#4: Combination (#2+#3) 22 0,75
Seasonal Energy Efficiency Ratio:
10WQSEER cold
el 60.QQSEERdrive
coldth
Valorisation of low-grade waste heat | Felix Ziegler | 9
Pressure
Temperature
Vapour pressure depression„mechanical potential“
Water
Aqueous Solutio
n
Liquid-Vapour-Equilibrium
„Honigmann“ cycle: storage and conversion of low-grade heat
Valorisation of low-grade waste heat | Felix Ziegler | 10
pressure
temperature
Charging (Heat!)
pressure
temperature
Discharging (work!)
Valorisation of low-grade waste heat | Felix Ziegler | 11
Honigmann fireless locomotive (1883)
Quelle: Mähr, Vergessene Erfindungen
Valorisation of low-grade waste heat | Felix Ziegler | 12
in
out
in
out
in
out
in
out
in
out
in
in
in
out
out
Temperature of heat flow
upgraded:T3=120°C
source: T2=80°C
work: T→∞
cold: T0=5°C
ambient: T1=35°C
#1 #2 #3 #4 #5
High source:T4=180°C
Valorisation of low-grade waste heat | Felix Ziegler | 13
Efficiency Example
#1 Work-driven heat pump 23
33TT
TWQCOP
g 9.4COP
#2 Heat-driven heat pump 23
24
4
3
4
3TTTT
TT
QQCOP
g 1.1COP
#3 Power cycle 2
12
2 TTT
QW
g 06.0
#4 Heat transformer 13
12
2
3
2
3TTTT
TT
QQCOP
g 29.0COP
#5 Heat-driven refrigerator 01
12
2
0
2
0TTTT
TT
QQCOP
g 43.0COP
Valorisation of low-grade waste heat | Felix Ziegler | 14
Relative heat turnover Example (see Table 2)
#1 Work-driven heat pump COPQQ3
i 12 1.8
#2 Heat-driven heat pump 23
i
2
#3 Power cycle 12
W
Qi 32
#4 Heat transformer COPQQ3
i 2 6.9
#5 Heat-driven refrigerator COPQQ0
i 22 6.7
Valorisation of Low-Grade Waste Heat
Felix Ziegler | Institut für Energietechnik
There are many challenging / promising options
Efficient heat transfer is key to implementation
Valorisation of low-grade waste heat | Felix Ziegler | 16
Q 2
Q 1
Q 0
Steam ejector cycle
Throttle
Condenser
Evaporator
Boiler
Pump
Ejector
Valorisation of low-grade waste heat | Felix Ziegler | 17
combustion engine
Steam jet cycle
com
pres
sor
turb
ine
exhaust hx
CAC
RHX
Valorisation of low-grade waste heat | Felix Ziegler | 18
Valorisation of low-grade waste heat | Felix Ziegler | 19
25 30 35 40 450
10
20
30
40
50
60
1,0 l/s
3,8 l/s
2,0 l/s
1,5 l/s
Heat sink temperature, inlet [°C]
Coo
ling
capa
city
[kW
]
Phydraulic = nominal=100%
Phydraulic = 1/64*nominal= 1,5%
Rückkühlvariationen (Biene)@ t_FW=90°C, m_FW=0,9kg/s, t_KW=21/16°C
Valorisation of low-grade waste heat | Felix Ziegler | 20
Valorisation of low-grade waste heat | Felix Ziegler | 21
Flexible Be- und Entladung Nutzung von Abfallwärme
Keine Selbstentladung
Vorteile des Prozesses
Valorisation of low-grade waste heat | Felix Ziegler | 22
Single-effect absorption chiller
Q1´´
Q0
EV
K
V
Q2
A
Q1´
LEVLP
LWT
G
A solution circulates between absorber A and regenerator G.
In the Regenerator G it is regenerated, consuming the driving heat.
The absorbed refrigerant isvaporised again.
In the absorber it absorbsrefrigerant vapour, rejecting heat.
Valorisation of low-grade waste heat | Felix Ziegler | 23
Q1´´
Q0
EV
K
V
Q2
A
Q1´
LEVLP
LWT
GThe refrigerant is liquefied in the absorber, rejecting heat...
Valorisation of low-grade waste heat | Felix Ziegler | 24
Q1´´
Q0
EV
K
V
Q2
A
Q1´
LEVLP
LWT
G
The vapour flows to the absorber, again.
...and is vapourised again in the evaporator, consuming
heat (producing cold).
The refrigerant is liquefied in the absorber, rejecting heat...
