Energy reducing retrofit apparatus for a constant volume HVAC system

• US 9,933,178 B2
• Filed: 04/17/2015
• Issued: 04/03/2018
• Est. Priority Date: 08/20/2009
• Status: Active Grant

• Current Assignee: Pro Star Energy Solutions LLC
• Original Assignee: Transformative Wave Technologies LLC (Performance Mechanical Group)
• Inventors: Miller, Danny, Sipe, Justin
• Primary Examiner(s): Norton, Jennifer L
• Application Number:
  US14/689,344
• Publication Number:
  US 20150219355A1
• Time in Patent Office: 1,082 Days
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/58 using Internet communication
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 2011/0006 using low temperature external supply air to assist cooling
• CPC Class Codes: F24F 2110/20 Humidity
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: F24F 2110/70 Carbon dioxide
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 19/05 Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
• CPC Class Codes: G05B 2219/1133 Sensor actuator, asi, bus, network
• CPC Class Codes: G05B 2219/25289 Energy saving, brown out, standby, sleep, powerdown modus for microcomputer
• CPC Class Codes: G05B 2219/2614 HVAC, heating, ventillation, climate control
• CPC Class Codes: G05D 23/1919 characterised by the type of controller
• CPC Class Codes: G05D 7/0676 by action on flow sources G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/125 involving control of end-device applications over a network
• CPC Class Codes: Y02B 30/54 Free-cooling systems
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
• CPC Class Codes: Y02B 30/90 : Passive houses; Double facade technology

Abstract

An energy-reducing method and apparatus for retrofitting a single zone, constant volume HVAC system, with or without an economizer, that provides heating, cooling, and ventilation to occupants within a building space. The present invention includes the introduction of a programmable logic controller and variable frequency drive (VFD) that takes control of the existing fan, heating, cooling, and optional economizer operation. The reduction of the fan speed in the ventilation mode when the 100% operation is not needed saves significant energy of the existing constant volume HVAC system where the fan motor is designed to run 100% of the time.

Claims

1. An efficiency enhancing controller (EEC) for enhancing energy efficiency in an indoor space of a building having an occupancy that is served by a single zone constant volume HVAC system, the EEC comprising:

(a) a programmable logic controller adaptable for the single zone constant volume HVAC system and configured to receive input signals from sensors and a thermostatic device and send control heating, cooling, and ventilation instructions or an occupancy command to;

(1) a fan assembly, including a fan motor configured to operate in a range of fan motor speeds, of the constant volume HVAC system to ventilate an indoor space in a building, and

(2) a heating assembly that can send heat to the indoor s pace, and

(3) a cooling assembly that can send cooling to the indoor space; and

(b) a variable frequency drive (VFD) that is configured to receive signals from the programmable logic controller and is configured to control the speed of the fan motor;

(c) a discharge air sensor or current status switch in order to provide fault detection comprising detection of a fan fault, a heat/cool (temperature-based) fault, and an energy consumption fault;

wherein the programmable logic controller is configured to reduce the fan motor speed via the VFD when the sensors indicate that the indoor space is less than fully occupied.

2. The EEC of claim 1 wherein the programmable logic controller and the VFD form a single unitary device.

3. The EEC of claim 1 further comprising a circuit logic that is configured to run whenever the EEC is operating and is set:

(a) to gather average outside air temperature, heat mode runtime, cool mode runtime, and ventilation mode runtime information at preset intervals to form sampled energy consumption amounts;

(b) to scan an internal database that comprises time of day and outside air combination information in order to find a matching combination; and

(c) to compare sample energy consumption amounts against the internal database.

4. The EEC of claim 1 further comprising a central processor and an interconnection configured to network the programmable logic controller with one or more controllers.

5. The EEC of claim 4 wherein the interconnection is wireless.