An assessment of the financial efficiency of a heat recovery system from graywater in a hotel

Abstract

The purpose of the article is to determine the profitability of investing in a graywater heat recovery system in a hotel facility located in south-eastern Poland whichis dependent on three heat sources for the domestic hot water preparation system, i.e. gas boiler, biomass boiler and electric heater. There were also various options for accommodation use: 25%, 50%, 75% and 100% occupancy of the hotel. The research was focused on the most frequently used methods for the absolute assessment of the effectiveness of investment projects enabling the creation of an objective criterion. Thus, both the simple method - Simple Pay Back Period SPBP and dynamic methods based on the discount account were used in calculations: Net Present Value NPV, Internal Rate of Return IRR, Profitability Index PI, Discounted Pay Back Period DPBP. The analysis also includes the annual increase in the purchase price of energy carriers. The conducted research has shown that in most cases the installation of the DWHR (Drain Water Heat Recovery) system is beneficial and profitable to the investor.

Opportunities and Threats of Implementing Drain Water Heat Recovery Units in Poland

“…It should also be noted that energy consumption for showering in residential buildings may even exceed 60% of water-related energy use [27]. The result is that by using a suitable heat exchanger both the amount of energy used for the preparation of hot water, as well as costs incurred for this energy are reduced [28].The variety of devices dedicated to the recovery of energy contained in the wastewater allows their use in virtually any situation. However, there are no projects promoting this form of energy saving, making DWHR units unpopular among potential users and investors.…”

“…It should also be noted that energy consumption for showering in residential buildings may even exceed 60% of water-related energy use [27]. The result is that by using a suitable heat exchanger both the amount of energy used for the preparation of hot water, as well as costs incurred for this energy are reduced [28].…”

Heat recovery and water reuse in micro-distilleries improves eco-efficiency of alcohol production

“…The concept of PV is frequently used in assessing the profitability of long-term investments, including for heat recovery (e.g. as part of net present value, NPV, calculations) (Fierro et al, 2020;Kordana et al, 2014;Lim et al, 2006;Mazur, 2018;Nemet et al, 2012;Spriet and McNabola, 2019). It takes into account that the value of money (here: the savings) changes over the lifetime of the project.…”

Assessment of the Feasibility of Implementing Shower Heat Exchangers in Residential Buildings Based on Users’ Energy Saving Preferences

“…This result should be considered unfavorable from the point of view of implementing shower heat exchangers. The conducted research [43,69] shows that the use of wastewater heat recovery systems is particularly profitable when domestic hot water is heated with an electrically powered device. In the case of hot water heaters, it is also possible to supply preheated water to both the shower mixing valve and the heater, which is the most cost-effective solution.…”