NEWEL-3 DC24TR NEWE3 Series Heat Recovery User Manual
- May 15, 2024
- NEWEL-3
Table of Contents
USER MANUAL
HEAT RECOVERY
DC24TR NEWE3 Series Heat Recovery
Digitel reserves the right to modify the technical characteristics described
without prior notice.
Non-contractual document
Digitel SA
All rights reserved
HEAT RECOVERY
1.1. INTRODUCTION
The reader of this document must read the chapter Error! Reference source not
found. Error! Reference source not found. before reading the rest of this
manual. It contains all the basic information indispensable to understand this
document and the concept of the NEWE3 series.
This manual describes the operation of the modules in terms of heat recovery.
Parameter [r1] of the operating mode is therefore programmed to 2.
1.2. GENERAL DESCRIPTION. BASIC CONNECTIONS
Heat recovery is handled by two DC24TR modules.
The principle of operation is shown in Figure 1.2.1. The connections are made
according to Figure 7.2.2
Control of heat recovery functions normally when the following conditions are met:
- The temperature difference (probe A1 – probe B) is greater than the value of parameter [S1]
- Contact C1 closed. At least one compressor is running.
- C2 closed. Recovery request.
- C3 closed. Auto control mode.
- C6 closed. Pump in order.
- C7 closed. No leak detected.
- C8 closed. Emergency cooling is not running.
- No sensor fault is detected.
Otherwise, the control is deactivated. The three-way valve cuts the flow of
fluid through the heat exchanger and pump PK2 is stopped. Contacts C4 and C5
manually bypass the blockage and operate the control at level 1 and level 2,
respectively, regardless of the conditions above.
In normal operation, when the temperature of sensor C drops below the value of
parameter [t1], level 1 of the recovery is activated. In this mode, output K1
controls the three-way valve VK1 and passes the hot gas into the heat
exchanger. After the delay set in parameter [S2], pump PK2 is activated in the
low flow regime. The control maintains the temperature of the outlet of the
exchanger (probe A) to the value set in parameter [E1] by acting on the
opening degree of valve VA1. This is PID control. Its behaviour can be tuned
by adjusting parameters [E4] (proportional coefficient), [E5] (integration
coefficient) and [E6] (differential coefficient). Valve VK1 is closed when the
temperature of probe E exceeds the value of parameter [t2]. Pump PK2 stops
after the delay programmed in parameter [S3].
Level 2 of the recovery is activated when temperature sensor B remains below
the value of parameter [t3] longer than the value of parameter [t5]. Output K3
is activated to cause upward shifting of the high pressure set point and the
gas cooler set point in the corresponding controls. Output K3 also activates
the high speed of pump PK2. Level 2 is stopped when temperature sensor E rises
above the value of parameter [t4]. The control then returns to level 1 (output
K3 is disabled, the offsets of the HP and cooler set points are removed and
the pump returns to the low flow mode).
To avoid wasteful operation at level 2, temperature B1 is monitored. When it
rises above the value of parameter [S4], after a time delay [S5] output K4 is
enabled, the operation at level 2 is interrupted and the control returns to
level 1. When temperature B1 drops below [S4], output K4 is switched off after
the programmed delay in [S6]. From that point, level 2 can be activated again
after timeout [t5], if necessary.
1.3. EMERGENCY COOLING
With the opening of contact C8, the “emergency cooling” mode is activated. In
this mode, valve VK1 is controlled and the hot gas is passed into the heat
exchanger; valve AP1 regulates the water temperature, but pump PK2 is stopped.
An alarm is triggered.
1.4. PRESSURE MONITORING
The pressure in the hot water circuit is monitored by pressure switch C7. When
it rises too high (e.g. due to leakage of CO2), contact C7 opens. In this
case, valve VK1 shuts off the hot gases in the heat exchanger and output K5 is
controlled to isolate the recovery circuit of the hot gas circuit with valve
VK5.
[E1] Set the water temperature (Settings menu)
[E4] PID – P control (Settings menu)
[E5] PID – I control (Settings menu)
[E6] PID – D control (Settings menu)
[t1] Level 1 start temperature (Settings menu)
[t2] Level 1 stop temperature (Settings menu)
[t3] Level 2 start temperature (Settings menu)
[t4] Level 2 stop temperature (Settings menu)
[t5] Level 2 start delay (Settings menu)
[S2] Pump start delay (Settings menu)
[S3] Pump stop delay (Settings menu)
[S4] B1 temperature limit – fault recovery (Settings menu)
[S5] K4 start delay (fault recovery) (Settings menu)
[S6] K4 stop delay (fault recovery) (Settings menu)
1.5. PARAMETERS
**Basic configuration
**
Sym.| Lev.| Operation| Rem.| Default value| Min|
Max
---|---|---|---|---|---|---
PAS| 0| Password| | 0| |
r1| 3| Operating mode| | 2| |
0 = Cooler 1 = Pressure control 2 = Heat recovery
Ad| 3| Module address
| Do not change when the module is connected to a DI58 / DC58 central unit!
| | |
Settings with r1 = 2 Heat recovery
| Sym.| Lev.| Operation| Rem.| Default
value| Min| Max
---|---|---|---|---|---|---|---
PAS| 0| Password| | 0| 0| 999
Control| E1| 2| Set the water temperature (° C)| | 45.0| 0| 90.0
E2| 2| Minimum opening of the valve VA1 (%)| | 20.0| 0| 100
E3| 2| Maximum aperture of the valve VA1 (%)| | 100| 0| 100
E4| 2| PID – P control (proportional coefficient) (%)| | 30| 0| 100
E5| 2| PID – I control (integration coefficient) (%)| | 30| 0| 100
E6| 2| PID – D control (differential coefficient) (%)| | 30| 0| 100
Levels 1/2| t1| 2| Level 1 start temperature (° C)| | 45.0| 0| 90.0
t2| 2| Level 1 stop temperature (° C)| | 50.0| 0| 90.0
t3| 2| Level 2 start temperature (° C)| | 42.0| 0| 90.0
t4| 2| Level 2 stop temperature (° C)| | 48.0| 0| 90.0
t5| 2| Level 2 start delay (min.)| | 5.0| 0| 900
Safeties| S1| 2| Minimum temperature difference (sensors A1-C; ° K)| | 10.0|
0| 60.0
S2| 2| Pump start delay (dry)| | 20.0| 0| 60.0
S3| 2| Pump stop delay (min)| | 0.0| 0| 60.0
S4| 2| B1 temperature limit – fault recovery (° C)| | 50.0| 0| 100
S5| 2| K4 start delay (fault recovery) (min)| | 10.0| 0| 450
S6| 2| K4 stop delay (fault recovery) (min)| | 10.0| 0| 60.0
Time, date| H1| 1| Hours settings| | 5| 0| 23
H2| 1| Minutes settings| | 8| 0| 59
H3| 2| Day and month settings| | 1| 1| 31
H4| 2| Month settings| | 1| 1| 12
H5| 2| Year settings| | 0| 0| 99
H6| 2| Day of the week settings| | 5| 1| 7
Alarms| Alarm code
---|---
13| Pump fault
17| Auxiliary mode does not respond
18| Recovery failure
19| Emergency cooling
20| Probe A failure
21| Probe B failure
22| Probe C failure
24| Probe E failure
25| Probe F failure
26| Probe A1 failure
27| Probe B1 failure
28| Pressure – leak detection
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