Modeling Time Period Information 建模时间周期

Heat exchangers potentially can change the ground temperature- especially when the cooling and heating loads are unbalanced. In such cases, it can take several years or more before the ground temperature stabilizes. With Ground Loop Design, designers can change the modeling time period (1 year, 5 years, 10 years, etc) and then calculate the heat exchanger length for that time period.
热交换器能改变地下土壤的温度,特别是当冷热负荷不平衡的时候。在这种情况下,地下温度可能需要几年甚至几十年才能达到稳定。对于地下环路设计,设计师可以选择不同的建模时间周期(1年/5年、10年,等等)进行模拟,然后计算出相应的热交换器管长。
 

For example, in an unbalanced system the soil temperature will be changing over time and therefore, the loopfield length will be changing (most likely increasing) over time as well. If a system is unbalanced, designed with a one year modeling period and then installed, it is possible that the heat exchanger will not be long enough to function effectively in the soil conditions 5 years out and the system will fail.
例如,在一个不平衡的系统中,地下土壤温度将随时间变化的,因此,环路域的管长将随时间变化(一般都是管长增加)。此时如果设计时按照一年的时间进行建模设计并安装,很可能系统管长在5年后不满足正常运行要求,从而导致整个系统的失效。

Hence, in some cases it is worthwhile to model over longer time periods and see when and at what length the heat exchanger length stabilizes (it stabilizes when the ground temperature stabilizes). For residential systems, ground temperature changes are uncommon since the systems are fairly small and usually relatively balanced.
因此,在某些情况下,有必要进行更长时间周期的建模,看何时何种长度的热交换器能实现系统的稳定运行(表现为地下土壤温度的稳定)。住宅系统的地下温度变化不常见,因为住宅系统相当小,通常都是相对平衡的。

A number a factors can influence the time it takes for the ground temperature to stabilize including: load balances/imbalances, water flow in the soil (flowing water can transfer heat quickly), and borehole depth. For shallow boreholes, a significant percentage of the borehole interacts with the atmosphere/ sunlight and hence has some of the characteristics typically associated with a horizontal system. Such systems tend to have reduced or no soil temperature changes since the soil can exchange heat with the atmosphere. For such systems, short modeling periods oftentimes can be used. As the boreholes get deeper, a greater percentage of the borehole is not affected by sunlight/the atmosphere and hence, long term soil temperature changes become more common.
对地下温度达到稳定所需时间有影响的因素包括:负荷平衡与否、土壤内部的水流量(流动的水将迅速传递热量)、井孔深度。浅的井孔通常与水平埋管系统类似,有相当大的比例与大气/阳光相互作用。由于土壤与大气的热交换,这样的系统土壤温度变化不大或没有变化。我们常常对这种系统进行短期的建模。井孔越深,其受大气/阳光的影响越小,长期的土壤温度变化更常见。

As with all engineering designs, it is ultimately the responsibility of the designer to choose the appropriate design inputs.
对于所有的工程设计,设计师有责任选择合适的设计输入。