Serial production

Serial production makes it possible to configure multiple productions in series, without any switching valves. The following figure shows on the left the base circuit and on the right the parameter windows that pops up when you click on the base circuit. The numbers indicate which circuit is the primary and secondary gate.

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The formulas behind this base circuit are the following:

• P1 + P2 = P

• V1 = V2 = V

• Or, in words: constant volume flow through both gates, while adding the powers together for the total power.

The parameter window has three different parameters that determine the operation of this base circuit. Namely ‘Partial load design temperature’, ‘Primary power’ and ‘Primary power percentage’.

* Watch out when filling in the ‘primary power’ parameter. It is possible to fill in a higher ‘primary power’ than what the end units need. see example 2 for more info.

Examples

In the first example, we’re going to show the effect all the different parameters.

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Example 1: Partial load design temperature

As you can see, the ‘Primary power’ overwrites the value of the ‘Partial load design temperature' and the ‘Primary power percentage’ overwrites the ‘Partial load design temperature' and ‘Primary power'. These changes are noticeable when you compare the different heat flows and temperature regimes.

In the second example, we’re going to show an error that is not shown as an error.

The problem is that value filled in the ‘Primary power’ is higher than the power needed in the end units, in this example 210 kW when the end unit needs 200 kW. This causes the temperature regime of the primary gate to be 61/40 and power 210 kW. This abundance of heat flow and supply temperature needs to be solved by the secondary gate. The base circuit connected to the secondary gate will work as a chiller to solve the surplus of power and supply temperature although a boiler cannot work as a chiller.

Common errors

Switchable serial production

The switched serial production is very similar to the serial production, the only difference is that it’s made switchable through switching valves. The following figure shows on the left the base circuits of switched serial production on supply (top base circuit) and on return (lower base circuit) and on the right the parameter window that pops up when you click on the on return base circuit. The numbers on the base circuit indicate which gate is the primary and secondary gate.

The formulas behind this base circuit are the following:

• P1 + P2 = P

• V1 = V2 = V

• Or, in words: constant volume flow through both gates, while adding the powers together for the total power.

The parameter window has three different parameters that determine the operation of this base circuit. Namely ‘Primary power’, ‘Primary power percentage’ and ‘Power propagation’.

* Watch out when filling in the ‘primary power’ parameter. It is possible to fill in a higher ‘primary power’ than what the end units need. see example 2 of serial production for more info.

** The two options are: ‘Regular’ and ‘Full load on auxiliary unit’

The parameters of the balancing valve, three way on-off valve and the actuator doesn’t change the operation of this base circuit. The kv and kvs-parameters determine the pressure drop over the corresponding valve and that impacts the sizing of the pump but not the operation of this base circuit. The minimal pressure drop determines the required pressure drop over the valve and the actuator parameter is only relevant when you choose manufacturers in the 'catalog'-menu. For more information on the three way valve’s parameters, the user is referred to Control valves.

Examples

All these examples use the same installation with an equivalent radiator capacity of 200 kW. The only thing that changes are the parameters on the switched serial production base circuit.

For the first example, both models have a ‘primary power’ of 120kW filled in. The difference is that the models have a different switchable serial base circuit installed.

Although both models have the same primary power filled in, the boilers work on different temperature regimes. With the switchable serial on supply, the temperature regimes are 40/52 and 52/60. Witch the switchable on return, the temperature regimes are 40/48 and 48/60. This difference is a consequence of the filled-in primary power. This primary power relates to the heat flow in the circuit connected to the primary gate and the temperature regimes adjust accordingly.

For the second example, both models have a heat flow of 120kW filled in on the ‘Primary power’. The difference is that the three models have different ‘power propagation' filled in.

When the switchable serial production base circuit is set to ‘regular’. The primary power is propagated on the primary gate and the rest, total demand minus primary power, is propagated on the secondary gate. The temperature regimes adjust according to the power distribution. When the switchable serial production base circuit is set to ‘full load on auxiliary unit’, the primary power is also propagated on the primary gate and the full demand is propagated on the secondary gate.