1. A system comprising: a plurality of heat pump systems; a plurality of CPUs, each CPU associated with one of the heat pump systems; and a management device adapted to manage the plural heat pump systems to bring a total amount of energy consumed by the heat pump systems closer to a target value, the management device comprising: a control unit including a processor configured to execute a stored program; a communication interface; and a database, the control unit being configured to execute the stored program to receive a total requested value of energy consumption as the target value from a higher-level energy management device via a communication network, allocate requested energy consumption amounts and incentives to the heat pump systems based on the total requested value of energy consumption and based on response characteristics of consumers having the heat pump systems in order to satisfy the total requested value of energy consumption, each of the incentives being a monetary reward amount, transmit individual consumption requests to each of the heat pump systems via the communication network, each of the individual consumption requests including the requested energy consumption amount and the incentive allocated to a different one of the heat pump systems, receive actual values of energy consumption from each of the heat pump systems via the communication network, each of the actual values of energy consumption corresponding to one of the individual consumption requests, respectively, and learn how each of the heat pump systems responds by conducting an analysis of the individual consumption requests and the actual values of energy consumption, and to update the response characteristics of the consumers to reflect results of the analysis; and the database storing the response characteristics, the response characteristics being correlations between the monetary reward amounts and actual amounts by which energy consumed by each of the heat pump systems was adjusted in response to the requested energy consumption amounts, the control unit being configured to create a list of the heat pump systems arranged from a top of the list in descending order with respect to a degree to which each of the consumers has cooperated with the individual consumption requests, the degree being determined based on the response characteristic of each of the heat pump systems so that a value of the degree is larger for consumers who cooperated with the request to adjust energy consumption in return for a smaller monetary reward amount, the control unit being configured to allocate the requested energy consumption amounts consecutively to the heat pump systems starting from the top of the list until the total requested value of energy consumption is satisfied, the control unit being configured to transmit the allocated energy consumption amounts to the individual heat pump systems as additional individual consumption requests, the CPUs of the heat pump systems being configured to create operation plans in response to the additional individual consumption requests and control the heat pump systems in accordance with the operation plans.