Structural Design of the mCCHP-RES System - Design for Micro-Combined Cooling, Heating and Power Systems - page 209

Many load sharing strategies can be imagined. To exemplify, two typical

strategies are presented, namely:

Power driven load sharing (when excess power does not appear), and

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Heat driven load sharing (when excess heat is avoided).

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Further, the Sect. 7 shows their application to the evaluation of the potential
structural models (models that were developed in Sect. 4 ). The aim is to identify
and eliminate those models that appear as less ef

cient.
A. Power driven load sharing for an off-grid system is based on the following
basic assumptions:

First, the power load will be shared on the power suppliers so that any excess
power did not occur.

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Then the heat load will be shared by the heat suppliers so as not to appear any
heat de

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cit.

The risk of a possible excess of heat load will be mitigated by modulating one of
the suppliers, according to complementary assumptions.

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As a theoretical exercise, in Fig. 29 it shows the application of the power driven
load sharing in a hypothetical case.
Here:

Lines PQ and MN show the evolution of the monthly power load and heat load
for entire system, during a calendar year.

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Surfaces PQRS and MNRS are the annually power load and heat load of the
system, respectively.

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(PV panels load) full and (ST panels) full are the surfaces UaVU and UbVU
respectively, and represent the annually load of the PV panels and ST panels
when they are working at their full installed capacity.

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(SE power load) is the surface PQRVaUS, represents the annually power load of
the Stirling engine, and is given by relation:

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ð SE power load Þ ¼ ð Power load PQRS Þ ð PV panels load Þ full

￿ (SE heat load) is the surface IJKLRS, represents the annually heat load of the

Stirling engine, and is given by relation:

ð SE heat load Þ ¼ ð SE power load Þ=c

￿ (Boiler load) is the pair of surfaces JIM and KLN, represents the annual heat

load of the boiler, and is given by relation:

ð Boiler load Þ ¼ ð Heat load MNRS Þ ð SE heat load Þ;

only positive values.

(Heat excess) is the surface JcKdJ and represents the heat remaining.

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