Stirling Power Cooler LPC-RL - Stirling Cryogenics

SC.1.1.1003
Stirling Power Cooler LPC-RL
Reliquefaction of boiling gases
The Liquid Power Cooler - Re Liquefier (LPC-RL) is the solution
for applications in which the design of a system allows:
• sufficient cooling by natural flow, and
• the boil-off gas developed by the application will collect
easily at the top of the application cryostat.
The liquid cryogen (neon, nitrogen, argon, methane, etc.) inside
the application cryostat or storage vessel evaporates as a result
of the energy given off by the application.
The boil-off gas that is formed collects at the top of the cryostat.
The gas is fed through a vacuum jacketed (VJ) line to the Stirling
cryogenerator where it is re-liquefied. It then flows back to the
application cryostat through another VJ line by gravity. The liquid
cryogen spreads throughout the application by natural flow,
thereby refrigerating the application.
The system should allow the liquid to disperse throughout
the zones where cooling is required. If this does not occur, hot
spots can occur counteracting the cooling process.
For temperatures below 77 K, the prevailing pressure is kept
below atmospheric pressure, down to 0.2 bar(a) for 65 K
using nitrogen. When using neon, the temperature can be as
low as 26 K at 0.5 bar(a).
The temperature of the cryogenerator cold head is monitored
continuously. If the temperature starts to drop, the capacity of
the cryogenerator is reduced and vice versa. This compensates
for the variation in the heat load from the application.
A small regulated heater is incorporated at the cold head to prevent
the liquid from freezing. The LPC-RL is fully automatic. When
operating normally, it does not require any operator attention.
NITROGEN Capacity [W] Power input [kW] Cooling water
65 K 77 K 65 K 77 K [l/h@15°C]
Re-liquefaction
• LPC-1 RL
• LPC-2 RL
• LPC-4 RL
700
1.400
2.800
1.000
2.000
4.000
12
24
48
11
22
44
750
1.500
3.000
NEON • LPC-8 RL
5.600Capacity [W] 8.000
96 Power input 88
Cooling 6.000 water
26 K 36 K [kW] [l/h@15°C]
Re-liquefaction
• LPC-1T RL
105
140
11
750
• LPC-2T RL
210
280
22
1.500
• LPC-4T RL
420
560
45
3.000
• LPC-8T RL
820
1.120
90
6.000
All specifications at nominal operating conditions. All data are subject to alteration without prior notice.
Pictures are intended to present a general idea of the products.
Stirling Cryogenics BV, Science Park Eindhoven 5003, 5692 EB Son, The Netherlands
a
company

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Stirling Power Cooler GPC
gas power cooler
The Gas Power Cooler (GPC) uses pressurized helium gas
(typically 20 barg) as medium to transfer cold to the application.
as a shield for the 20 K loop, maximizing the cooling power
available to the 20 K target.
The GPC is a two-stage Stirling cryogenerator which
simultaneously provides refrigeration at 20 K and at 80 K
by means of two separate heat exchangers. Each of them
consists of a wound spiral tube and a cold gas pump. The two
pumps circulate the gas in seperate loops, from the two heat
exchangers in the application (where energy in injected into
the medium) to the GPC (where energy in extracted from the
medium).
The GPC is connected to the application by two delivery
and return lines ducted together in a single flexible vacuum
insulated line. This offers flexibility for the positioning and
installation of the GPC (up to a radius of 10 meters). In both
the application and transfer lines, the 80 K loop can be used
Operation of the GPC is fully automatic. It runs down to the
lowest possible temperature depending on the application
load. If required, the GPC can be equipped with a set-point
controller that maintains a fixed temperature regardless of
fluctuations in the application load.
The delivery of a GPC system consistst of a two stage
cryogenerator with two cold gas pumps and optional flexible
connection lines.
The figures mentioned below are only an indication, correct
values can only be given after detailed technical discussion and
optimization.
GAS POWER COOLERS
Capacity [W]** Power input Cooling water
20 K/80 K 20 K/80 K 30 K/80 K He gas flow [kW] [l/h@15°C]
• GPC-1
75/0
50/400
90/400
Will be a result
11
750
• GPC-2
150/0
100/800
180/800
of customers
22
1.000
• GPC-4
350/0
200/1.600
360/1.600
process conditions.
45
3.500
** simultaneously at 2nd stage ad 1st stage
All specifications at nominal operating conditions. All data are subject to alteration without prior notice.
Pictures are intended to present a general idea of the products.
Stirling Cryogenics BV, Science Park Eindhoven 5003, 5692 EB Son, The Netherlands
a
company

SC.1.1.1003
Stirling Power Cooler FF
forced flow liquid cooler
with pump cryostat
The Liquid Power Cooler - Forced Flow (LPC-FF) transfers energy
generated by the customers application (i.e. HTS power cables,
etc.) to the cryogenerator via a closed loop of liquid gas. The
LPC‐FF consists of the Stirling cryogenerator, a pump cryostat
and connecting lines.
This LPC-FF type is effective for those applications where the
application does not allow sufficient cooling by natural flow only.
In this application sub cooled nitrogen (10 - 15 K below its boiling
point) is used. Therefore the heat dissipated by the application
only causes a temperature raise. As there is no boiling there will
be no gas bubbles. This assures that the complete application is
always fully filled with liquid, providing for optimal heat exchange.
The warmed LN 2
(still sub-cooled) re-enters the LPC-FF flowing
through a heat exchanger which heats up the buffer serving as a
thermal mass.
In the heat exchanger the LN 2
is cooled down and pumped
through the application again by means of a cryogenic pump.
A second volume is connected parallel to this application loop. This
volume incorporates a heater to increase pressure throughout the
system to ensure that the liquid remains sub-cooled. It also acts
as an expansion vessel to compensate for density fluctuation.
In the buffer tank liquid nitrogen will be boiling. The nitrogen
boil‐off is fed to the Stirling cryogenerator through a vacuum
jacketed (VJ) line where it is re-liquefied. The LN 2
flows back to
the buffer through a VJ line by gravity. In order to regulate the
temperature of the buffer the pressure is controlled between 0,2
bar(a) for 65K and 1 bar(a) for 77K. As the heat exchanger between
the buffer tank and the application loop can be considered ideal,
the temperature of the LN 2
at the exit of the heat exchanger will
be the same as the LN 2
in the buffer tank.
The LN 2
exit temperature of the LPC-FF is measured continuously.
The cryogenerator capacity is reduced if the temperature starts to
drop and vice versa. This compensates for the heat load variation
of the application.
The system can be equipped with the hardware and software
needed to permit a “soft cool down” from ambient to its operating
temperature and for initial filling and start up. Refrigeration mode
is fully automatic and does not require any operator intervention
to run or regulate it. Manual operation of certain valves is only
needed when modes are changed or in temporary modes.
The cooling capacity of the LPC-FF system will depend on several
operating parameters like allowable ΔT across the application and
required ΔP. These conditions and the associated pump losses
result in a calculated flow through the application.
The figures mentioned below are only an indication, correct
values can only be given after detailed technical discussion and
optimization.
NITROGEN
Capacity [W] Liquid gas flow Power input [kW] Cooling water
65 K 77 K and ΔP 65 K 77 K [l/h@15°C]
• LPC-1 FF
500
840
Will be a
13
12
750
• LPC-2 FF
950
1700
result of
26
24
1500
• LPC-4 FF
2450
3750
customers process
53
49
3000
• LPC-8 FF
4500
7300
conditions.
106
98
6000
All specifications at nominal operating conditions. All data are subject to alteration without prior notice.
Pictures are intended to present a general idea of the products.
Stirling Cryogenics BV, Science Park Eindhoven 5003, 5692 EB Son, The Netherlands
a
company