Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
TECHNICAL-ECONOMIC COMPARISON OF UNITARY AIR CONDITIONING AND VRF SYSTEMS FOR HIGH STANDARD RESIDENCES IN MANAUS CITY
Submission Author:
Mateus Rodrigues de Andrade , AM , Brazil
Co-Authors:
Mateus Rodrigues de Andrade, João D'Anuzio Lima de Azevedo
Presenter: João D'Anuzio Lima de Azevedo
doi://10.26678/ABCM.COBEM2023.COB2023-1377
Abstract
Energy consumption in Brazilian dwellings has been continuously increasing, most of which is due to air conditioning. According to data from PROCEL, air conditioners are present in 22% of Brazilian homes. However, there are distortions in electricity consumption as a function of family income. In high-end residences, which the salary range is above 20 minimum wages, the contribution of air conditioning represents 35.4% of total consumption. In Amazonas, hot and humid most of the year, such equipment is present in 43% of households and is often considered the “great villain” in the electricity bill. For this reason, the search for more efficient equipment has intensified recently. However, even in high-end homes, the use of these technologies is limited by economic viability, because small VRF systems can be 2 to 5 times more expensive than conventional systems. Therefore, the present work evaluated the technical-economic viability of different air conditioning strategies for high-end residences in Manaus city. For this, two dwellings with 416.7 m² (House A) and 138.7 m² (House B) were selected, which two systems types were analyzed, the split (inverter) and the VRF. The annual hourly cooling load was estimated considering hypotheses of continuous and sporadic use for the smaller household. The thermal performance and consumption curves were obtained from technical catalogs and manufacturer information, allowing the estimation of the annual electrical consumption of each system. The economic feasibility study was carried out using the cash flow method based on the initial investment, the acquisition and installation costs and the energy savings generated by each system. The results showed that, in terms of energy, the VRF system is advantageous for both residences, as annual consumption is 41% lower in House A and 38% lower in House B, compared to the system with inverter splits. In addition, the payback of the VRF system proved to be attractive for the two residences with continuous use mode, as the financial return occurs in less than 3 years. On the other hand, in the case of recreational housing for sporadic use (House B), the unitary system with inverter splits becomes more advantageous since its initial investment is 64% lower than the VRF. Furthermore, in this B-house scenario, the VRF system had a very long payback (9.5 years), close to the end of its useful life, making its application unfeasible.
Keywords
Split, vrf, feasibility study
