Expediency of substitution of water heating with air heating involving use of heat pumps

Expediency is considered of substitution of water heating and transition to air heating that can be implemented with “air-air” type heat pumps (HP). The absence of water pipelines raises the reliability of heating systems. In addition to improved reliability, heat pumping systems ensure comfortable conditions for consumers at intervals between the heating seasons, when the central water heating is disabled.

The “air-air” type HP use the ambient air as a low-grade heat source (LGHS). At low air temperatures, transformation ratio μ is about 2 and would rise to 3÷4 at higher air temperatures, which ensures high cost-efficiency of heating systems based on heat pumps. The heating season can generally be divided into two periods. One of the periods is characterized by the highest ambient air temperatures (–5÷8°С). This period is rather long and, in warmer winters, can last for about 4000 hours per heating season, or longer. This is the period, when the heat pump operates efficiently at a transformation ratio above 4.

The other period, when the ambient temperature falls below –10÷ –20°С, generally lasts for a small number of hours, which makes about 15÷18% of the total duration of the heating season. At this period, the efficiency of the heat pump would decrease to μ =1.9÷2. Yet, even with such an efficiency, a heat pump delivers twice as much heat as the electric power it consumes.

Therefore, in regions with a long period of temperatures within the range of –5÷8°С during a heating season, air heating based on HP can be advantageous compared to water heating.

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