Waste heat recovery system controller

In a refrigeration system having a heat exchanger for extracting and recovering heat from the superheated refrigerant by means of a transfer fluid, apparatus for controlling the flow of the transfer fluid comprising:

• pump means for causing transfer fluid to flow through the heat exchanger, said pump means having a controllable flow rate;
• temperature sensing means disposed so as to sense the temperature of transfer fluid at the outlet of the heat exchanger;
• and
• control means, operatively connected to said temperature sensing means and to said pump means, for controlling the flow rate of said pump means in a manner proportional to the outlet temperature of the transfer fluid, said control means having modulator means for varying input power to said pump means and compensation means for maintaining the stability of operation of the resulting control function.

In a refrigeration system having a heat exchanger for extracting and recovering heat from the superheated refrigerant by means of a transfer fluid and a fluid transfer pump apparatus for controlling the flow of the transfer fluid comprising:

• thermistor means disposed so as to sense the temperature of the inlet transfer fluid for producing an electrical signal proportional to the temperature of the transfer fluid;
• a comparator connected to said temperature sensing means and to the pump for disabling operation of the pump when the temperature of the transfer fluid exceeds a first pre-selected value, said comparator for comparing such electrical signal to a pre-selected reference signal representative of the first pre-selected value, wherein said comparator producing a pump disabling pulse when the electrical signal exceeds such first pre-selected reference signal;
• and
• said comparator connected to said thermistor and to the pump for controlling the pump to operate when the temperature of the transfer fluid is less than a second pre-selected value, such second pre-selected value being lower than such first pre-selected value, said second comparator for comparing electrical signal to a second pre-selected reference value, said second comparator producing a pump enabling pulse when the electrical signal is less than such second pre-selected reference signal.

In a refrigeration system having a heat exchanger for extracting and recovering heat from the superheated refrigerant by means of a transfer fluid, apparatus for controlling the flow of the transfer fluid comprising in combination:

• pump means for causing transfer fluid to flow through the heat exchanger, said pump means having a controllable flow rate;
• first temperature sensing means disposed so as to sense the temperature of transfer fluid at the outlet of the heat exchanger;
• pump control means, operatively connected to said first temperature sensing means and to said pump means, for controlling the flow rate of said pump means in a manner proportional to the outlet temperature of the transfer fluid;
• second temperature sensing means for sensing refrigerant temperature at the inlet to the heat exchanger, said pump control means connected to said second temperature sensing means and responsive thereto for allowing the pump to operate only when such refrigerant temperature exceeds a first pre-selected value;
• third temperature sensing means disposed so as to sense the temperature of the transfer fluid to be heated in the heat exchanger;
• high temperature control means connected to said third temperature sensing means and to said pump control means for disabling operation of the pump when the temperature of the transfer fluid exceeds a second pre-selected value;
• and
• low temperature control means connected to said third temperature sensing means and to said pump control means for controlling the pump to operate when the temperature of the transfer fluid is less than a third pre-selected value, such third pre-selected value being lower than such first pre-selected value.

In a system having a waste heat recovery subsystem utilizing a heat exchanger and a transfer fluid, apparatus for controlling the flow of the transfer fluid comprising in combination:

• pump means for causing transfer fluid to flow through the heat exchanger, said pump means having a controllable flow rate;
• first temperature sensing means disposed so as to sense the temperature of transfer fluid at the outlet of the heat exchanger;
• pump control means, operatively connected to said first temperature sensing means and to said pump means, for controlling the flow rate of said pump means in a manner proportional to the outlet temperature of the transfer fluid;
• second temperature sensing means for sensing the waste heat medium temperature at the inlet to the heat exchanger, said pump control means connected to said second temperature sensing means and responsive thereto for allowing the pump to operate only when such waste heat medium temperature exceeds a first pre-selected value;
• third temperature sensing means disposed so as to sense the temperature of the transfer fluid to be heated in the heat exchanger;
• high temperature control means connected to said third temperature sensing means and to said pump control means for disabling operation of the pump when the temperature of the transfer fluid exceeds a second pre-selected value;
• and
• low temperature control means connected to said third temperature sensing means and to said pump control means for controlling the pump to operate when the temperature of the transfer fluid is less than a third pre-selected value, such third pre-selected value being lower than such first pre-selected value.