建筑节能技术必须依靠有能力的控制系统。直接数字控制（DDC）和比例积分（PI）控制技术为实现建筑物冷冻水系统中温度、压力和流量的复杂控制提供了先进的方法。然而，PI控制是为线性、时不变系统开发的。由于冷冻水系统是高度非线性的动态系统，当系统负荷变化时，微调PID控制可能会变得不稳定。不稳定的控制系统会降低冷冻水系统的能量和热性能，并缩短控制系统的寿命。因此，需要在一次系统级别进行高级控制，以将一次系统的控制与二次系统的非线性联系起来。传统的方法是设计特殊的控制阀来补偿非线性冷冻水系统。不幸的是，暖通空调系统的动态特性无法通过具有固定特性的控制阀进行补偿。 本文介绍了传统控制方法和创新的集成控制线性化方法的理论模型和仿真。该模型综合了不同负荷分布下的主冷冻水泵扬程和水回路压差。通过理论建模和仿真对二次系统进行了表征，以揭示关键控制特性以及这些特性对集成系统控制和能量性能的影响。该研究得出结论，一次冷冻水回路中的压差对二次系统的控制性能和稳定性有很大影响。非线性特性可以通过一种集成方法动态降低，重新设置供水温度和压力控制。引用:ASHRAE论文CD:2014 ASHRAE冬季会议，纽约

Building energy efficiency technologies have to rely on capable control systems. The direct digital control (DDC) and proportional and integral (PI) control technologies provide an advanced approach to accomplish the complex controls of temperature, pressure and flow in the building chilled water systems. However, the PI controls are developed for linear, time-invariant systems. Since the chilled water systems are highly non-linear dynamic systems, a fine tuned PID control may become unstable when system loads change. The unstable control system will degrade the chilled water system energy and thermal performance and also reduce the control system life span. Therefore, superior control is required at the primary system level to link the control of the primary system with the nonlinearities of the secondary system. The conventional approach is to design special control valves to compensate nonlinear chilled water systems. Unfortunately the dynamic characteristics of HVAC systems cannot be compensated by the control valves with fixed characteristics. This paper presents the theoretical model and simulation on traditional control methods and an innovative integrated control linearization approach. The model integrates the primary chilled water pump head and water loop differential pressure under differing load distributions. Characterization of the secondary system was conducted through theoretical modeling and simulation to reveal the key control characteristics and the impacts of such characteristics on the control and energy performance of the integrated system. The study concludes that the differential pressure in the primary chilled water loop substantially impacts the control performance and stability of the secondary system. The nonlinear characteristics can be dynamically reduced through an integrated approach, resetting the water supply temperature and pressure control.