热泵选型计算

A 正确的热泵选型计算可同时避免过小（性能差）与过大（短周期运行、资本浪费）。下述方法同样适用于空间供暖、生活热水与工艺热回收。

Step 1 — Define the Load

从峰值供热或供冷负荷（kW）开始。对于回收用途，应按稳定的工艺负荷而非偶发峰值来选型。与以下进行交叉核对 AHU 选型计算 当泵服务于空气处理机组时。

Step 2 — Match Capacity at Design Conditions

Heat pump capacity drops as the sink (heating) temperature rises or the source temperature falls. Always read capacity from the manufacturer’s performance map at your design source and sink temperatures, not at the rating point.

输入	对容量的影响
供水温度更高	容量下降，COP 下降
热源温度更低	容量下降，COP 下降
除霜循环（空气源，低温）	Effective capacity down 5–15%

Step 3 — Check COP and SCOP

比较季节 COP（SCOP），而非仅看名义 COP。考虑空气源机组的除霜损失与部分负荷性能。一个 高温热泵 以部分 COP 换取更高的可输出温度。

Step 4 — Size the Source and Sink Loops

对于废热源，请确认流量与温升足够。参见 热泵废热回收 与 污水源热回收 以进行源侧设计。

Step 5 — Verify the Payback

请使用我们在以下方法中所采用的同一框架，将增量资本与年度节能相权衡 工业废热回收案例。为使回收期切合实际，请将泵按稳定负荷合理选型。

Beyond First Cost

Selection is not only about matching a nameplate capacity. The pump will spend most of its life in part-load, part-temperature conditions, so review the seasonal performance curve, not just the rating-point COP. Where the heat source is variable such as a wastewater or exhaust stream, size the evaporator and buffer to the minimum expected source temperature, and add control logic that sheds or stages the load instead of letting the compressor hunt. Consider the working fluid and the maximum allowed discharge temperature when a high-temperature delivery is required, since that constrains the refrigerant choice. Finally, document the assumptions: design source and sink temperatures, flow rates, and defrost strategy. A selection file that records these lets commissioning confirm the unit actually meets the modeled capacity and COP, which is the only way the payback calculation stays honest.

常见问题

Why should heat pump capacity be read at design conditions rather than the rating point?
Capacity and COP both fall as the sink temperature rises or the source temperature drops, so the rating-point figure overstates real-world performance.

What is the difference between COP and SCOP?
COP is the instantaneous efficiency at given conditions, while SCOP is the seasonal average across the whole operating season including part-load and defrost losses.

How does defrost affect air-source heat pumps?
In cold weather, periodic defrost cycles reduce effective delivered capacity, which must be subtracted when sizing the unit.

How should variable waste-heat sources be treated in selection?
Confirm the flow and minimum temperature are sufficient for the evaporator, and add staging or buffer controls so the unit does not short-cycle on a variable source.

常见问题

Why should heat pump capacity be read at design conditions rather than the rating point?

Capacity and COP both fall as the sink temperature rises or the source temperature drops, so the rating-point figure overstates real-world performance.

What is the difference between COP and SCOP?

COP is the instantaneous efficiency at given conditions, while SCOP is the seasonal average across the whole operating season including part-load and defrost losses.

How does defrost affect air-source heat pumps?

In cold weather, periodic defrost cycles reduce effective delivered capacity, which must be subtracted when sizing the unit.

How should variable waste-heat sources be treated in selection?

Confirm the flow and minimum temperature are sufficient for the evaporator, and add staging or buffer controls so the unit does not short-cycle on a variable source.