Central Plant with Plate Heat Exchanger (PHE) – Airoverse

| Overview

The Plate Heat Exchanger is equipment in the chiller circuit, that favors the transfer of energy from the cooling to the heating side and vice versa.

It can be an efficient addition to the chiller circuit, that could use free cooling and reduce the load on the chiller thereby reducing the energy consumption required to run the chiller. This means if conditions are favorable the plate heat exchanger could provide the required cooling for the building load.

It can also be used to provide water at a slightly higher temperature to provide the heating for the building during winter, thus reducing the effort required from the AHU to heat the space, which also leads to energy savings.

| Inclusions

A chiller circuit can favor both cooling and heating, either with the plate heat exchanger or boiler that supplies the heating load and the cooling tower for the corresponding cooling load.

The header pipes that connect both these pieces of equipment to the circuit will have to carry both the hot water/chilled water based on the building load.

To support such a case a new type of header pipe that can carry both hot and chilled water to support the cause is introduced as a "dual temp header pipe" equipment.

| Connections

The connections and interactions remain the same as for another circuit except for the new equipment introductions.

Using the required equipment, and following the required steps to connect the equipment the below chiller circuit is achieved.

Here we have the plate heat exchanger which will serve as a non-contact heat exchanger between any two circuits such as condenser/chilled water or hot water/condenser water etc.

It will have a primary side and a secondary side based on the heat exchanger application. The objective here may be to lower the load on the chiller, get some free cooling on the building & even lower the cooling tower load.

Due to the above possible scenarios, the projects can come across. Even the building load equipment should start to support a two-pipe system that will carry chilled water or hot water as per building needs.

Hence the child pipe equips of the building load equipment will also be of dual temp nature.

There could also be a possible use of the bypass pipe equipment as implemented earlier, color of the header pipes and the building load sub-equips will be determined by the equipment that is running.

This means when the chiller is running then the dual temp headers and building load equips will be represented in blue and red if the boiler is running.

| Example Applications

PHE between cooling tower and building load via the dual temp header pipe:

Here the non-contact heat exchange is between the cooling tower-supplied condenser water and building return water, via the header.

Here the PHE primary side will be connected to the cooling tower and the secondary side to the building via the dual temp header.

PHE between a chiller supply and return header after the bypass pipe equipment to the building

Here the PHE will facilitate heat exchange between the chiller plant and the building load.

A bypass pipe equipment with a two-way valve will regulate the heat exchange by controlling the bypass.

Here the plant side will be the primary side of the PHE and the building load will be secondary respectively.