Optimised heat pump system

Abstract

A system for space heating or cooling a heated space includes a heat pump including a refrigeration circuit for transferring heat between a heat source and a heat load for heating and cooling operations. A controller controls the heat pump to perform the heating and cooling operations. A user interface receives user inputs, wherein the user inputs include an indication of discomfort based on temperature. The controller creates a profile for a minimum comfortable temperature level and a maximum comfortable temperature level, and the controller controls the heat pump to perform the heating and cooling operations in accordance with the profiles for the minimum and maximum comfortable temperature levels. The controller may generate an optimized heat demand plan in accordance with predictions of outdoor and indoor temperature, cost, and demand. The plan is optimized to cost-effectively maintain the temperature of the heated space within the comfortable temperature range defined by the profiles.

Description

TECHNICAL FIELD[0001]This invention relates to heat pump systems, controllers and their user interfaces, and in particular electrical heat pump systems with a variable cost source of electricity, such as photovoltaic panels.BACKGROUND ART[0002]Heat pumps are known to be an efficient means of facilitating heating or cooling applications, comparing favourably against the primary energy requirements of fossil fuel or biomass boilers. Improved efficiency is considered desirable to consumers as it can deliver lower operating costs. With respect to all HVAC (Heating, Ventilation and Air-Conditioning) systems, it is well-accepted that costs can also be lowered by reducing the amount of heat that must be added or removed from a building. However, reducing heating or cooling demands can leave occupants thermally uncomfortable, so the user of an HVAC system will generally target a compromise between thermal comfort and cost.[0003]For heat pump systems, the daily cost of heat transfer is an in...

AI Technical Summary

Benefits of technology

The present invention relates to a system controller for a heat pump that aims to minimize operating costs while still providing comfortable temperatures for the user. The system controller expands the available range of heat demanded by the system using minimum and maximum profiles for comfortable temperatures. This allows for flexibility in minimizing operating costs by moving heating or cooling to a time when the cost of heating or cooling is lower. The space can also be heated above the minimum set-point or cooled below the maximum set-point so that future heating or cooling demands are reduced. The system controller achieves this by expanding the available range of heat demanded by the system and optimizing the compression ratio of the heat pump based on the available heat demand. This technology provides a cost-efficient and flexible solution for managing heat transfer in a system.

Problems solved by technology

Also, increasing heating or cooling beyond the mean comfortable level increases exergetic losses from a temperature-regulated space.

Therefore, marginal increases in stored energy impose ever-greater marginal costs.

Additionally, for a system with fixed capacities of heat absorbers and heat emitters, stable heat pump output yields the maximum average COP (Coefficient of Performance).

Lower power consumption during other periods does increase COP but it does not fully compensate for the degradation in performance during high power consumption periods.Predictability: To cost-efficiently apportion heat transfer throughout a day, it is necessary to make predictions of the variability in marginal electricity cost during that period.

Errors in the predictions can require greater variability in heat pump consumption which, as explained above, leads to performance degradation and higher operating cost.

Solutions in the prior art are limited to a heat demand plan based on set-point targets for building and storage temperatures.

Such solutions are inflexible for the purpose of daily cost optimisation.

This is not normally done, for example, in the case of heating with a gas boiler where any extra heating beyond the minimum set-point leads to increased losses and higher operating costs.

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