L. Bujedo1*, J. Rodriguez2, P. J. Martfcnez3, and J. Vicente1

1 CARTIF, Parque Tecnologico de Boecillo Parc 205, 47151 Boecillo, Spain
2 Institute for Renewable Energy, EURAC Research. Viale Druso 1, 39100 Bozen/Bolzano. Italy
3 University Miguel Hernandez, Av. De la Universidad s/n, 03202 Elche Spain
* Corresponding Author, luibuj@cartif. es

Abstract

The present work, describes the main features of a software developed by the research centre CARTIF under the programming environment LabVIEW ®, which allows to visualize all of the variables collected by means of the installation’s instrumentation to measure different values (temperatures, flows and pressures), and the meteorological station (direct and diffuse radiation, ambient temperature, relative humidity, etc.), and its subsequent exploitation.

The program apart from calculating the identification parameters for the different elements: performance curves for the collectors, efficiency of the heat exchanger, looses on tanks or hydraulic performance, allows the analysis of the system along a time period in a particular date doing a balance of the energetic variables during this period. With the previously recorded values is calculated the average performance for the different elements.

This program has been very useful for other works based on simulation using TRNSYS, as it shows directly the values to be introduced on the model in order to compare the real system and the simulated one.

Keywords: solar cooling, identification, performance, LabVIEW ®.

1. Introduction

As [1] establish one of the problems that solar cooling installations have to face is “the lack of practical experience and acquaintance among architects, builders and planners with the design, control and operation of these systems”.

Despite there are an important number of operative installations, there is no information related to their exploitation. Among the causes can be found: insufficient monitoring of the different heat flows, what prevent to close the power balances. Some of the errors usually committed, can be for example the lack of flow measures because there are constant flow pumps, and with the system working the flow must be constant as well. Nevertheless the experience becomes evident that it is not like this, since the more elemental change on the hydraulic structure of the installation modify the value of this flow, such as for example to feed the generator with the boiler or to do it with the solar installation.

Another problem is to use measuring systems that does not allow to store the values into files, and so sometimes, it must be done a manual collection of the data measured.

On the contrary to have measures of temperatures, flows and pressures and record they periodically
(0.5 minutes), make possible the analysis of the installation performance or the identification of the

different elements and posterior modelling. Allows as well, detection of operation or design failures. The authors would like to highlight the importance that monitoring has for installations as a way to know what is happening and a tool obtain conclusions to learn from the things well done as well as for those wrong.