The most widely used home heating appliances in Argentina are the balanced flue gas space heaters. The reasons for this choice may be found in their affordable cost and in the comfortable and secure indoor environment generated (i.e., indoor air is not employed for combustion while flue gas is discharged outside). However, the units that are currently marketed have an important disadvantage: their relatively low thermal efficiency. Measurements made in our laboratory for a balanced flue gas space heater with independent inlet (for the fresh air) and outlet (for the flue gas) ducts, yielded values of around 73% for the maximum power (2.9 kW), while for the minimum power (1 kW) are reduced to 61%. Those values are directly related to the outlet temperatures of the flue gas stream of about 400 °C and 240 °C for maximum and minimum powers, respectively. In this context, it is of major interest to develop and implement alternatives to improve the thermal efficiency of such type of devices.

In a previous contribution we proposed to employ a heat exchanger (designed ad-hoc) to take advantage of the relatively high enthalpy of the flue gas to preheat the fresh inlet air. This alternative was implemented in a balanced flue gas heater and encouraging results were reached, as the discharge temperature of the flue gas stream could be considerable reduced, but certain limitations arose, which are revisited in this article.

The aim of this contribution is to present the advances in the design and manufacture of a new heat exchanger applicable to a different type of balanced flue gas heaters. The results obtained in the test-runs are reported and analyzed. It is anticipated that a remarkable improvement in the thermal efficiency was achieved.

阿根廷使用最广泛的家用加热设备是平衡式烟气空间加热器。这种选择的原因可能在于它们负担得起的成本以及产生的舒适安全的室内环境（即，不使用室内空气燃烧，而烟气排放到室外）。然而，目前上市的装置有一个重要的缺点：它们的热效率相对较低。在我们的实验室中对具有独立入口（用于新鲜空气）和出口（用于烟气）管道的平衡烟气空间加热器进行了测量，得出的最大功率 (2.9 kW) 的值约为 73%，而最小功率的值约为功率 (1 kW) 降低到 61%。对于最大和最小功率，这些值分别与大约 400 °C 和 240 °C 的烟道气流的出口温度直接相关。在这种情况下，开发和实施替代方案以提高此类设备的热效率具有重要意义。

在之前的一篇文章中，我们建议使用热交换器（专门设计的）来利用烟气相对较高的焓来预热新鲜入口空气。这种替代方案在平衡的烟气加热器中实施并取得了令人鼓舞的结果，因为烟气流的排放温度可以显着降低，但出现了某些限制，本文将重新讨论这些限制。

此贡献的目的是介绍适用于不同类型的平衡烟气加热器的新型热交换器的设计和制造方面的进展。报告和分析在测试运行中获得的结果。预计实现了热效率的显着提高。