Characterization of cooling loads in the wine industry and novel seasonal indicator for reliable assessment of energy saving through retrofit of chillers

Abstract

The food sector is a major consumer of energy and growing efforts are being made in the search for solutions that will guarantee the efficient and sustainable use of energy resources. Among the different sectors, wineries are attracting particular interest due to the continuous growth of the global market and production. Surveys conducted in the winemaking sector have highlighted the importance of performing accurate energy audits and have identified the installation of efficient refrigeration systems as a promising solution in a variety of cases. Unfortunately, the savings achievable by efficient cooling technologies are often estimated using simplified approaches which do not take into consideration the actual operating conditions of the equipment typically variable on seasonal and daily bases. In this paper a novel bottom-up procedure is presented, aimed at developing reliable profiles for refrigeration and airconditioning loads and at assessing the extent to which more efficient chilling units could contribute to reducing electricity consumption. The use of standard Seasonal Energy Efficiency Ratios is critically discussed and a novel customized indicator is proposed. The method is applied to a medium-scale winery producing still red and white wines and sparkling wines, for which only aggregated energy consumption data are available. After deriving detailed load profiles, it is proven that the use of standard seasonal indicators leads to 56.85% and 83.87% overestimation of potential energy savings, respectively, for low and medium temperature cooling energy uses, confirming the importance of adopting seasonal indicators customized on the actual operating conditions of chillers. Keywords Energy saving, wineries, energy audit, cooling load, industrial chillers, seasonal energy efficiency ratio *Revised Manuscript with No Changes Marked Click here to download Revised Manuscript with No Changes Marked: Revised manuscript-clean file.docx strategies based on heat pumps in the food and drink industry. Despite the great research efforts, large margins for improvement of food processing plants still exist. 1.1 Sustainability issues and assessment in wineries Among the food industries, the winemaking sector has been attracting a growing interest due to the high energy intensity of wineries and the consequent concern about their impacts in terms of energy and freshwater consumption, greenhouse gas emissions and production of pollutant residues. In order to assess the sustainability of wine industries, a first step consists of identifying appropriate impact indicators and benchmarks. A study by Martins et al. [6] identified a set of indicators covering the environmental and economic levels of "sustainability". The study compared the sustainability of two Portuguese wines, and a lifecycle analysis allowed the identification of the "winemaking" phase as the most relevant for energy intensity, while the "bottling" phase resulted as the highest contributor to carbon emissions indicator. Gilinsky et al. [7] carried out a comp...

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“…The study resulted in a reduction of energy consumption of 39.6%, when compared to a traditional room air conditioner. Catrini et al 36 performed a study on saving energy in the food industry, more specifically the wine industry. By retrofitting the chillers used in this assessment, it was concluded that the use of standard seasonal indicators leads to 56.9% and 83.9% overestimation of potential energy savings, for low and medium temperature cooling energy uses, respectively.…”

Choice of the Optimal Design and Operation of Multi-Energy Conversion Systems in a Prosecco Wine Cellar

“…The assessment of the actual energy demands of the cellar is the first fundamental step for any proper energy audit. In the wine-making sector this is not an easy task because, as highlighted also in [13], the energy demands are strongly variable on seasonal and daily bases, and a direct measurement of the consumption of the many involved devices would be too expensive (the only available information on consumptions usually derives from monthly or annual bills). To this end, the main steps of the wine production have been deeply analyzed (Section 2.1) to obtain as accurate as possible consumption profiles of each step, and therefore of the entire process (Section 2.2).…”

“…where ϕ in,i (t) is the energy flow (power) associated with the main input to a unit (fuel), ϕ out,i (t) is the energy flow (power) associated with the main ouptut of the unit (product), ϕ MAX out,i and ϕ MIN out,i are the maximum and minimum loads of the unit, respectively, K1 i and K2 i are (usually positive) parameters depending on the type and features of the energy conversion unit, and δ i (t) is a binary variable that identifies the on/off status of the unit. When δ i (t) = 0, Equations (12) and (13) give ϕ i,out (t) = 0 and so Equation (11) gives ϕ i,in (t) = 0, i.e., the unit is off. When δ i (t) = 1, Equations (12) and (13) let ϕ i,out (t) vary within the range of possible loads and the fuel consumption is calculated by Equation (11), i.e., the unit is on.…”

“…De Bortoli [11] and Paolino [12] analyzed in detail the design of machineries utilized in a traditional wine cellar. Catrini et al [13] proposed a new procedure to obtain reliable profiles for cooling needs of medium-scale wine cellars. The final goal is to have a precise basis for the assessment of the energy saving that can be achieved by installing more efficient compression chillers.…”