Heating and Cooling

Coordinator: Karel Kabele, CTU in Contributors: Eric Willems, Erwin Roijen, Peter Op 't Veld, Camilla Brunsgaard, & Mary-Ann Knudstrup, Aalborg University, Per Kvols Heiselberg, Tine S. Larsen, Olena K. Larsen, Rasmus Lund Jensen Arturas Kaklauskas, Audrius Banaitis, Vilnius Geniminas Technical University Marco Perino, Gianvi Fracastoro, Stefano Corgnati, Valentina Serra Werner Stutterecker, Mattheos Santamouris, Margarita Asimakopoulos, Marina Laskari, Zoltan Magyar, Mihaly Baumann, Aniko Vigh, Manuela Almeida, Sandra Silva, Ricardo Mateus, University of Minho Piotr Bartkiewicz, Piotr Narowski, Matthias Haase, Karel Kabele, Pavla Dvořáková, (CTU –

LECTURE 12 HEATING AND COOLING SYSTEMS CONTROL

Fundamentals of control; output control; safety control, predictive control; intelligent buildings.

FUNDAMENTALS OF CONTROL

What is it - Control system ? Device, which changes one or more parameters of the heating/cooling system – temperature – flow rate – pressure

Why to control heating/cooling system Output control according to actual heat loss Operation safety Restriction by operational parameters of heat source or any element of heating system Hydronic balancing

Control circuit Controlled variable x Manipulated variable y Disturbance variable z Command variable w Controlled system X Z Controller Y Actua tor Feedback W

Manipulation Controlled variable is changed by actuator No feed-back, no controller Controlled system X Z Actua tor ?

Hand actuated control Controller = man Controlled system X Z Y Actu ator Feed back W

Automatic actuated controll w and/or x activates actuator to achieve required value of x Controlled system X Z Regulátor Y Actu ator Feed back W

Control circuit Technical background Measurement of controlled and command variable – electronic thermometer, flow meter, pressure meter Controller – Compare measured values with required valuesa and activates actuator Actuator – Control valve, shutoff valve, three-way valve

Output sampling controllers Manipulated variable – on/off, 0-0,5-1 Example: room thermostat

Continuous action controllers Manipulated variable vs. Controlled variable = transition characteristic. – P - proportional – I – integral – D – shunt – T – time delay – … – Fuzzy logic – more variables

Controllers - energy Self actuated controllers – Energy from the controlled systém Electronic controllers Pressured air actuated controllers

Actuators Electromagnetic shut- off valves Control valves Mixing 3 or 4 way valves

Thermostatic valves Common With remote setup With remote sensor Radiator valve

Application of 3way valve

output control; safety control, predictive control; intelligent buildings

OPERATION OF HEATING AND COOLING SYSTEMS

Commissioning; Inspection; Fault detection, Operation, Energy audit Last developements in the heating/cooling field