Introduction; Overview Of The System; How The Heat Pump Works - Mitsubishi Electric ecodan EHPX-Serie Installationshandbuch

2. Introduction

2
Introduction
The purpose of this installation manual is to instruct competent persons how to
safely and efficiently install and commission the hydrobox system. The target
readers of this manual are competent plumbers and/or refrigeration engineers

Overview of the System

The Mitsubishi Electric Air to Water (ATW) for heat pump system with hydrobox
consists of the following components; outdoor heat pump unit and indoor hyd-
robox incorporating the main controller.

How the Heat Pump Works

Space heating and DHW
Heat pumps take electric energy and low grade heat energy from the outdoor air
to heat refrigerant which in turn heats water for domestic use and space heating.
The efficiency of a heat pump is known as the Coefficient of Performance or COP
this is the ratio of heat delivered to power consumed. The heat pump operates
most efficiently when generating low flow temperatures.
The operation of a heat pump is similar to a refrigerator in reverse. This process
is known as the vapour-compression cycle and the following is a more detailed
explanation.
Low temperature renewable heat
energy taken from the environment
2 kW
Electrical energy
input
1 kW
who have attended and passed the requisite Mitsubishi Electric product training
and have appropriate qualifications for installation of an unvented hot water hyd-
robox specific to their country.
The first phase begins with the refrigerant being cold and low pressure.
. The refrigerant within the circuit is compressed as it passes through the com-
2. The hot refrigerant gas is then condensed as it passes across one side of a
Heat energy output
3. Now as a cold liquid it still has a high pressure. To reduce the pressure the liq-
3 kW
4. The final stage of the cycle is when the refrigerant passes into the evaporator
It is only the refrigerant that passes through this cycle; the water is heated as it
travels through the plate heat exchanger. The heat energy from the refrigerant
passes through the plate heat exchanger to the cooler water which increases in
temperature. This heated water enters the primary circuit and is circulated and
used to serve the space heating system and DHW tank (if present in system).
2. Condenser
(Plate heat exchanger)
3. Expansion valve
4. Evaporator
(Outdoor unit air heat exchanger)
pressor. It becomes a hot highly pressurised gas. The temperature also rises
typically to 60°C.
plate heat exchanger. Heat from the refrigerant gas is transferred to the cooler
side (water side) of the heat exchanger. As the temperature of the refrigerant
decreases its state changes from a gas to a liquid.
uid passes through an expansion valve. The pressure drops but the refrigerant
remains a cold liquid.
and evaporates. It is at this point when some of the free heat energy in the out-
side air is absorbed by the refrigerant.
DHW tank
. Compressor
4