ScienceDirect IFAC-PapersOnLine 48-30 (2015) 450–455 Keywords: greenhouse; solar greenhouse; thermal energy; parabolic trough collector; smart grid; 1. INTRODUCTION Nowadays, the need for energy production efficiency is increasing due to higher environmental requirements. The concept of smart grid is more and more used not only in the power systems (Arghira 2012), (Camacho 2011), (Dragomir 2012), but also in connected fields (Marinescu 2014). Renewable energy resources (RES) offers multiple advantages and they are put to better use in small scale applications in domains such as agriculture, transport, industry, in order to improve energy management and consumption. A significant challenge associated with smart grids is the integration of renewable generation. In a traditional way, power systems have addressed the uncertainty of load demand by controlling supply. However, with RES, the uncertainty and intermittency on the supply side must also be managed. Demand response and load control, such as providing price signals or other incentives for consumers to modify their loads is already being practiced in commercial and industrial facilities to adjust consumption (Camacho 2011). With the accept put nowadays on ecological agriculture, the use of RES can be an effective answer to new issues. The interest in renewable energy sources for greenhouse heating is currently high and is still growing. One new solution to increase efficiency and flexibility for a greenhouse is to use a solar collector system for heating purposes. Although in the specialized literature have occurred various experimental solutions for a solar greenhouse, the accent was not on the benefits provided by using parabolic trough collectors for heating a greenhouse. An interesting solution for a solar greenhouse was developed by Esen and Yuksel from Turkey (Esen 2013). They proposed an experimental evaluation of using various renewable energy sources for heating a greenhouse and they have focused on the biogas, solar and a ground source heat pump greenhouse heating system. Also, an equivalent greenhouse climate model based on feedback-feedforward compensation technique responsible for linearization, decoupling and disturbance compensation of the greenhouse complex model was designed by Gurban and Andreescu, (Gurban 2012, 2013, 2014). A dynamic model for parabolic trough reflector has been presented by Leo et al. from France, (Leo 2014). This model describes the behaviour of the output steam parameters (pressure and enthalpy) and it can be used to develop a control strategy for a combined cycle power plant using the coupling of the collector with a conventional power plant. The present work aims to provide a thermal model for the Greenhouse Parabolic Trough Collector system (GHPTC) to ensure optimal growth climate conditions which leads to an increasing demand of high efficiency greenhouse control systems. Abstract: The paper proposes a system developed to provide heat for a greenhouse using parabolic trough collectors (GHPTC) thermal energy. In order to ensure perfect conditions of growth for greenhouse plants, the GHPTC control system regulates the internal temperature of the greenhouse and it monitors the temperature of the conducting fluid through collector pipes. The GHTPC model is composed of two subsystems: the greenhouse model and the parabolic trough collector model. Each of these models were validated using real data, considering as a validation index the maximum error between the real and simulated data on a period of one day (24 hours). The proposed GHTPC model shows an energy gain by increasing the greenhouse internal energy even with no control applied on ether of the subsystems. *Dept. of Automatic Control and Industrial Informatics, University Politehnica of Bucharest, Bucharest, Romania (e-mail: grigoriu.oana@gmail.com, nicoleta.arghira@aii.pub.ro, iliescu@shiva.pub.ro) **Dept. of Control Systems, GIPSA-lab, University Joseph Fourier Grenoble 1 Grenoble, France (alina.voda@gipsa-lab.grenoble-inp.fr) Ramona-Oana Grigoriu*. Alina Voda** Nicoleta Arghira*, Sergiu Stelian Iliescu* Modelling of Greenhouse using Parabolic Trough Collectors Thermal Energy Available online at www.sciencedirect.com 2405-8963 © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Peer review under responsibility of International Federation of Automatic Control. 10.1016/j.ifacol.2015.12.420 © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.