Assessment of waste heat recovery potential in greenhouse ventilation systems using dynamic pinch analysis

A Systematic Heat Recovery Approach for Designing Integrated Heating, Cooling, and Ventilation Systems for Greenhouses

“…Figure 2 shows the overview of the design methodology, which is structured into four sequential steps, namely, data preparation, energy targeting, HEN design, and technoeconomic analysis. This work is a sequel to our previous study [18] in which the former two steps were discussed in detail. In summary, to begin with, the required input data to fully define the streams listed in Table 1 (i.e., hourly thermal loads, ventilation rate, relative humidity, and temperature profiles) were generated using a greenhouse climate model.…”

“…This generic method is then applied to a case study greenhouse to design an integrated climate conditioning system enabling ventilation waste heat recovery. This study is a continuation of our previous work [18] in which heat integration was successfully accomplished by defining the greenhouse heating, cooling, and ventilation systems as a set of streams. A clustering technique, as the cornerstone of the method, was proposed to limit the problem size from a year to a few typical days.…”

“…In fact, by using typical days, the heat integration problem has been successfully limited to only a few typical scenarios that are repeated during the year. It should be mentioned that the detailed description of the clustering process, including finding the optimum number of typical days, accuracy of clustering, and algorithm selection have already been discussed [18] and are not reiterated here. Furthermore, to facilitate interpretation of the results in this study, all chosen typical days are categorized into three main climatic conditions.…”

“…Figure 1 shows the streams representing the suggested system annotated from 1 to 10 and the potential heat integration schemes in greenhouse heating and cooling modes. A detailed description of the streams can be found in our previous work [18] and is not reiterated here. Table 1 briefly presents the specifications of all streams in the system, including the source and target temperatures, as well as the heat capacity (CP = .…”

“…The buffer tank is sized based on the worst-case scenario for the coldest day of the year (TD1). The details of HP cycle design and condenser-buffer tank matching were described in detail in the energy targeting phase in an earlier publication [18]. Knowing the heating capacity of the HP, the natural gas boiler capacity can be simply derived by subtracting the HP heating capacity from that of TD1 in which the HP is sized based on the coldest day of the year (i.e., HP-only scenario).…”