US 7,434,413 B2Granted

Indoor air quality and economizer control methods and controllers

AssigneeHoneywell International Inc.

InventorRichard A. Wruck

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Abstract

Supervisory controllers, and methods, for use in a coordinated IAQ and economizer system. Various control objectives are defined and met. Some illustrative control objectives include economizer control, sequencing of economizer free cooling with compressor driven cooling, indoor air quality and FAV aims, demand ventilation settings, system protection from low temperatures, and smoke, supervisory and fault tolerance commands. The controller may be self configuring. A tiered fault tolerant controller is also provided. An illustrative controller is configured to determine whether various system sensors and devices are operational. The illustrative controller is also configured to perform a first method when all system sensors and/or devices are functioning, and at least a second method in response to sensor or device failures. The supervisory controller may include integrated economizer control, or may be configured as a separate controller. Supervisory controllers configured for use with specialized controllers are also illustrated.

Claims6

Dependent claims

An HVAC controller for use in an HVAC system, the HVAC system including:

a fan, cooling equipment, and fresh air ventilation components;
a return air enthalpy sensor for sensing system return air enthalpy;
and
an outside air enthalpy sensor for sensing outside air enthalpy;
a dry bulb sensor disposed to measure outside air temperature, wherein the dry bulb sensor is distinct from the outside air enthalpy sensor;
the HVAC controller configured to receive signals from the return air enthalpy sensor, the outside air enthalpy sensor and the dry bulb sensor, the HVAC controller adapted to perform the following steps:
determine whether the return air enthalpy sensor and the outside air enthalpy sensor are both functioning;
if both the return air enthalpy sensor and the outside air enthalpy sensor are both functioning, operating the HVAC system using an economizer mode having a differential enthalpy economizer decision process;
if the return air enthalpy sensor and the outside air enthalpy sensor are both not functioning, operating the HVAC system using a second mode that does not include a differential enthalpy economizer decision process;
determine whether the dry bulb sensor is functioning;
if the outside air enthalpy sensor is not functioning, and if the dry bulb sensor is functioning, operating the HVAC system using an economizer mode having an outside air dry bulb decision process;
and
wherein the HVAC controller is further adapted such that, if the outside air enthalpy sensor is functioning:
if the dry bulb sensor is not functioning, operating the HVAC system using an economizer mode not having an outside air dry bulb override decision process;
or
if the dry bulb sensor is functioning, operating the HVAC system using an economizer mode including an outside air dry bulb override decision process.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/032,460Filed 10 Jan 2005
Published: US 2006/0150644 A113 Jul 2006
Granted: 14 Oct 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification12 codes

F24F 11/62
Control or safety arrangements: characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or…
F24F 11/74
For controlling the supply of treated air, e.g. its pressure: for controlling air flow rate or air velocity
F24F 11/30
Control or safety arrangements: for purposes related to the operation of the system, e.g. for safety or monitoring
F24F 2011/0006
For ventilation: using low temperature external supply air to assist cooling