Question about Differential Controller (type 2)

["Jong, M.J.M." <jong@xxxxxx>]

Dear TRNSYS users,

At this moment I am busy with simulating a house with a solar collector on
it. The heat of the collector will be stored in a tank. To control the flow
through the collector I use the differential controller (type 2 in TRNSYS).
When the outlet temperature of the collector >10 °C than the temperature in
the top of the tank there will run a flow throug the collector. When the
outlet temperature < 2 °C than the temperature in the top of the tank, than
the pump will be switched off. 

I defined the controller, the pump, the ducts and the collector as you can
read below.
(Unit 50 is Stratified fluid storage tank (type 4)

UNIT 40 TYPE 1 COLLECTOR VOOR WARM TAPWATER
PARAMETERS 14
1  1 Oppcol Swarmte 1 77 0.56 18 0.0612 -1 4.19 1  0.0087 0.0963

INPUTS 10
46,1 42,2 0,0 14,2 14,7 11,16 DIFHOR 0,0 13,16 0,0
3.5  0    0   0    0    0     0      0.2 0     35

UNIT 41 TYPE 2 PUMP CONTROLLER POMP VOOR TANK WARM TAPWATER
PARAMETERS 4
7 10 2  60

INPUTS 4
40,4 50,3 40,4 41,1
5    20   5    0

UNIT 42 TYPE 3 PUMP VOOR TANK WARM TAPWATER
PARAMETERS 4
Debiet 4.19 Ppompcol  0.3

INPUTS 3
45,1 0,0    41,1
10.0 Debcol 0.0

UNIT 43 TYPE 31 Leiding van collector naar warmtewisselaar voor tapwater
PARAMETERS 6
0.038 30  6.3 1000.0  4.19 10.0

INPUTS 3
40,4 42,2 30,15
0    0    5

UNIT 45 TYPE 5 HEAT EXCHANGER TUSSEN COLLECTOR EN TANK VOOR WARM TAPWATER
PARAMETERS 4
2 129600 SWARMTE 4.19

INPUTS 4
43,1 42,2 48,1 42,2
0    0    0    0

UNIT 46 TYPE 31 Leiding van warmtewisselaar tapwater naar collector
PARAMETERS 6
0.038 30  6.3  1000.0  4.19 10.0

INPUTS 3
42,1 42,2 30,15
0    0    5

When I look at the flow through the collector, the outlettemperature of the
collector and the temperature in the top of the tank, I see that there will
be a flow when the outlet temperature of the collector << 10 °C than the
temperature in the tank. Sometime when the temperature difference is >> 10
°C there is no flow.

Does anybody know what to do to get the right control strategie ? 

With kind regards,



Maurice Jong.

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Maurice Jong
ECN - Energy Research Foundation      Department: Wind, Group DEGO
P.O. box 1    1755 ZG  Petten              Country:   The Netherlands
Telephone:    (+31) 224 564938             Fax:       (+31) 224 563214
E-mail: jong@ecn.nl
Internet:http://home.soneraplaza.nl/mw/prive/mjmjong/

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